I encourage players to get familiar with the game and read the official SSDT beginner's guide before starting to 100% complete the game.
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=518864299
If you need some tips for setting up, I advise to set short games, with no quarters, AI set on "training" difficulty, and no goalkeepers (though you will require different settings for different achievements). Maybe ban the American Football as it bounces randomly and can compromise some goals, but I unlocked all achievements with every ball allowed myself.



And of course, achievement hunting 101: make sure you have the Steam overlay activated while playing, an Internet access, etc. in order to get the achievements. This advice applies to all Steam games, so I'd guess you already know all that.

Win a game against the CPU in Quick Match


This achievement is literally the easiest and you probably already got it before reading this guide. You just have to win a quick match as described in the achievement's description.
If you're having trouble with that, I'd recommend using the settings I mentioned above (short game, training AI and no keepers). Make sure you play every quarter, have no human players in the opposite team, and of course, win the game.

Get 3 Hat Tricks in a quarter with the same player against the CPU


A hat trick is triggered each time one single player scores three times in the same quarter (you might be already familiar with that term if you've played Rocket League); you can recognize a hat trick with a special jingle playing, a goal celebration that is a bit longer and the audience throwing hats on the field (these do not affect gameplay). For this achievement, you'll need to perform three hat tricks with the same player (the AI can control this player, even though I would advise against that as it would make the achievement more complex) and within the same quarter. Play games with long quarters (you don't need to end the game to unlock the achievement) and the AI on easy, no goalies, short field and choose a character who can sprint quickly to dunk most of the balls; the Roller Derby player is a good choice for that.
You could also try aiming at the posts with another player such as the Baseball player, as it's the way to score with the fewest movements, but even the training AI can tackle you while doing that, so in my opinion, rushing and dunking instead is preferable.

You also can perform this achievement along with the achievement "ALL THE POINTS" below.

Score 35 points or more in a Challenge Mode match


This achievement works with any challenge from the challenge mode, though it is better to try with the challenge #1 (challenge #0 is too short, and the other challenges have higher AI difficulty, both are definitely not helping with a task that requires to score a dozen goals). Just get the Roller Derby player, grab the ball and dunk. Repeat.
You can score in the net if no one is around to defend as you'll score one additional point compared to simply dunking, but be really careful with the opposite team, you can't afford wasting time being tackled and losing the ball.
Do not lower your guard, especially in late game as the AI will be more aggressive and gain a difficulty level or two after a few hat tricks.

Speaking of hat tricks, you can try this achievement along with "THE HATTIEST OF TRICKS" achievement above.

Score the winning point with 0:00 on the clock in a match against the CPU


A really tricky one, you have to score and win during the last second of the match (that means in the last quarter), regardless of the hundreths of seconds, all the while losing or being in a tie beforehand.
My trick for this is to play the shortest match possbile (one quarter 30 seconds), with the AI set to training, no keepers, short arena, and every score type set on 1 point given per goal. Pick a fast class such as Football/Soccer player or Roller Derby player, wait for the "time running out" sound effect (if you have points to catch up on, do it now).
Now, the timer won't beep at the last second. If you've played the game for a while, you'll know what I'm talking about. Just keep yourself clear of opponents, focus on the timer and once it stops, score a goal.
!DO NOT DUNK!
At the time I'm writing this, a dunk does not trigger the achievement for various reasons. I've spent about 20 minutes trying to finish with a dunk before realizing this. I'll keep this guide updated if Tipping Goat fixes this. Until then, keep to a simple goal like the net.

Reach sudden death overtime in a match against the CPU


This achievement is quite simple, you can get it without actually trying. You just need to reach overtime. Make sure you have activated the "sudden death overtime" option in the scoring menu in the settings (otherwise, the game will call it a tie and end there).

If you want to get this achievement quickly, just pick a game with the settings I've described above (shortest game, no quarters, training AI...), wait for the timer to end (I would also advise setting every scoring point to 1 just in case). If both teams are tied, the game will start overtime and you'll get your achievement. You don't have to finish the match to get it.

Beat challenge level 10


This achievement requires to actually beat each and every challenge, as Challenge #10 is the last unlockable challenge. I'm not going to write an exhaustive walkthrough of all the challenges in SSDT, mostly because roughly two thirds if not more of them are really easy to complete. Maybe in another guide.
I am going to give a few tips for level 10 though. It's a Baseball vs. American football with no goalkeepers and tough AI. You're going to face a big offensive team and will need to rely on speed, dodging, and quick responses.
If you get the ball, make a lot of passes to destabilize the AI. Keep in mind that you can score with posts but shooting with the Baseball player takes a lot of time, so dunk as much as possible. It's a kind of hard level so I can't give better advice than practising often, and understanding how to play with both classes and how expert AI works with American footballers (a lot of rushes and tackles, but they're slow once they have the ball).

Can you get the fans to do "The Wave"?


It seems that the audience will do the wave at some point after scoring (usually when you get past 15 points, but I can't tell for sure). In the older game version, you could notice it more easily after scoring, but now that the game zooms in on the scoring player and sets a spotlight that darkens everything around, you will get it without even noticing during a regular game. If anyone can tip me in on what exactly triggers the audience to make a wave, I'll gladly add it to this guide.
gtm.steamproxy.vip/sharedfiles/filedetails/?id=1241089382
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1241106315

Score a goal by ricocheting a ball off the goal post


This one is easy enough, but you may need to focus on it, as you may not get the achievement without meaning to.
Get a net shooter like the Roller Derby player or the Hockey player, shoot a crooked shot to the net goal, if it hits the border and scores, you get the achievement.
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1241028875
I would advise setting up a quick match with easy or even training AI, no goalkeepers, then getting to the lower side next to the net and shoot while aiming up. You don't need to finish the match to trigger the achievement. I think it's possible to get it while playing a free-for-all game, but I'm not 100% sure. It's good for score training though anyway.

Win a free-for-all match against 5 CPU opponents


Set a 5 CPU free-for-all ("minigame?" button) game, put them on slow classes such as American Football or Basketball (NOT Hockey! They might KO your character with bowling balls or pucks). Take a quick striking class like Soccer/Football, Roller Derby, Hockey, or Baseball, spam the goal with shots, win the game because the opponents are too slow.
I have a preference for point blank net shots, but post shots are also good as opponents can't disrupt these.

Deflect 100 attacks using turbo


This achievement is just plain grinding. You'll eventually unlock it while doing the other ones, especially if you play classes such as Hockey player or Soccer/Football player. I don't have actual tips about this one besides dashing through your opponents while they're holding the ball. I got it while doing the challenges.

Can you break the scoreboard?


While this one has a confusing description, it only means you have to score over 99 points. As the scoreboard is limited to two digits, any team going over 99 points breaks the scoreboard and automatically wins the match. My advice for this one is to set a long game with the most and longest quarters possible, set all the scoring points to the max (5 points per goal), easy or training AI, no goalkeepers, and then spam the goal until you reach 99 points.
You will quickly know you've won because the horn sound effect will try to play then stop, and the scoreboard will glitch and break afterwards.
That's it.

Play for a total of 55:55:00


Classic time grinding achievement. I don't have any advice other than play, play again and replay that game. Try each class, try to beat an expert AI in 3v3, play long games. Everytime you invite friends over, offer to play a game or two.
I think you can also let the game running idle with a 1v1 without CPU players. Anyway, keep in mind that it only counts actual gametime.
UPDATE : So I just recieved a comment from the dev, they told me the game actually counts gameplay time (and not the one spent idle in the menu) and that said timer is only counting 55 minutes 55 seconds, they also specified that you'll no longer need to grind the game time at the next update, as you will definitely go over 55 minutes of gameplay by doing seasons and new achievements.