- have invested interest in wanting to push your mechanics as best as you can. without it all of this is useless. before everything else, have interest first

- don't run from being a failure. chase failure and those uncomfortable moments. whether you're in a slump, a bad mood, etc
play through those moments where you're at your lowest. this is where you improve the most
it's not only when you do good, it's when you embrace & persevere through your lowest moments during the journey that matters the most

- i'd encourage you to do these following commands: hud_saytext_time 0, voice_enable 0, !hud (in game chat) and hud_deathnotice_time 0
this will remove the fear of who you're added against, elo, or anything else that's at best a distraction. focus on yourself only.
i'm not a saint either being a victim of all of those things beforehand. you're not alone there

- use gunboats. you're forced to aim rockets carefully and precisely since you have no shotgun to secure the kill. and for purposes of improving long term, it's better to use gunboats for this reason
your rockets will drastically improve

- pay attention to the angle of your opponent's strafe and aim/flick ahead of your opponent's strafe pattern to juggle them. the better the opponent, the more difficult this is to do. however, the more you play
and familiarize yourself with patterns (most players move very similar because of class limitations i.e soldier has slow speed, large damage output but is projectile. has to aim at player pathways because of travel time.
scout has speed, but low hp. less likely to default to aggression off spawns)
the better you will be able to read them. this is the part that mostly comes down to how many reps you put in daily. intuition.

- patience. patience is the direct counter to deliberate player movement. why? because it reveals deliberate pathing or mistakes your opponent is making that you wouldn't see otherwise if you reacted to everything they did.
i.e mixing flat a/d strafing with diagonal/vertical pathing/consistently changing
distances simultaneously. a simple example of what to look for: a scout presses his "a" key (from your pov that would be your "d" key) and then suddenly, the scout presses his "d" key (from your pov, your "a" key) and then strafes right back
to the same position pressing his "a" key. you want to shoot a rocket AFTER he taps his "d" key, into his "a" key strafe. you ignore the smoking mirrors of his movement and look for the key window of opportunity/vulnerability to punish him
-> this also applies to fighting soldiers as well

- remember to keep a good mindset and take it easy on yourself if you don't see progress immediately. it's OK to take a break and think about what you might've done wrong during your losses, close games, or even wins once you have a collected head. don't give up.
focus on being the best that you can be and try your hardest.
that's what matters in the end

The general opinion on jumping/surfing in Ammomod is negative, especially with more experienced Ammomod players. I believe that a big reason for this is that play styles that use those techniques, in a lot of ways, defeat the purpose of the game mode. Some of the main points of Ammomod are to work on your ground movement (reading fakes, faking, etc.) and close/mid range dm skill. While you absolutely can improve on those aspects of your game play despite jumping or surfing, it can definitely hurt you more in the long run.

Either you jump/surf wrong and they make you more predictable, or you do them right and they become counterproductive because you aren't correctly prioritizing the things the arena is really meant for.

All in all, this is my stance on the issue. I've gained the knowledge I wrote here through general experience with the game mode as well as through mentorship, but don't take my word as 100% objective. Reach your own conclusions and more importantly than all else, have fun!