I first joined SteamGifts back in July 2016, and at first the idea behind the site seemed brilliant:
There are plenty of bundles being sold on various websites around the web.
They have games I'd like to play, and games I don't care about, and don't really need.
Other bundles I wasn't aware of, and aren't active anymore - so I can't get them.
And SteamGifts simply solved all that.
It both allows me to give away games I don't need or intend to play, while allowing me to win games I do want, but couldn't buy (or don't want to buy the whole bundle for a single game).

However, pretty soon the real state of affairs has revealed itself:
While you can give away games, and get plenty of interested people.
Once you try to enter giveaways for some nice game, you realize hundreds to thousands of other people have joined the same giveaways. So have practically no chance of winning.
And the games you do have a chance to win - you really don't want to play.
So after a few months of struggling with SteamGifts, and trying to understand how can I actually win any normal games there... I discovered SteamGifts groups.

The first group I joined was a great group called Giftropolis.
Which had some great people, and great giveaways.
Giftropolis was being run at the time, by its founder HyperDoll, who was spending a tremendous amount of work running the group.
At some point, HyperDoll started being overwhelmed by the effort to run the group and decided to step down.
I tried to help by creating a small automated tool to help her keep track of the giveaways in the group and make the effort of running the group a bit more bearable, but unfortunately, it was too little, too late.

When the group stopped being active, I started to look for another group to join instead, but couldn’t find one.
So I decided to start one myself, and make it all the things Giftropolis was, and more.
So I wanted the group to be:
Active (so every member needs to create at least 1 giveaway per month)
High quality (so people actually want to enter the giveaway in the group. And not for cards or +1 on games)
Fair (without people who only win games, while other people only give games)
A community (one of the best things in Giftropolis was that people were nice to each other)
and manageable (I didn’t want to spend all my non-existing free time managing the group, or keep a large staff of mods like other groups have)

So I created a recruitment thread and made some basic rules (mandatory giveaway once a month, 10p minimal game value on SG, no leeching, be nice, etc.). And invited all Giftropolis members to join.
At first, the group was open, so anyone who wanted to join, was able to do so. Which caused over 100 people joining in the first month alone.

One of the things that allowed me to manage such a large group on my own, without wasting all my free time or using an army of group admins, was the little tool I originally wrote for HyperDoll.
Initially, it took it 30-60 minutes to run, and it only calculated the number of created vs. won giveaways for each member.
But in time I enhanced and improved it, and it eventually grew up into an online service, constantly updated, which can monitor every entry of every giveaway in the group, and notify me of invalid giveaways, users breaking rules, and much much more.
You can see the current abilities of the tool here:
https://www.steamgifts.com/discussion/5vQp7/tool-sgmt-steamgifts-group-management-tool-open-source-tool-ive-been-working-on

So back at the newly formed QGG group:
At the end of the first month, I realized what a mistake was creating an open group when the SGMT tool showed me there was a group of members entering every giveaway created in the group, others entered giveaways while not giving anything back, and some were creating tons of giveaways from 100-for-$1 bundle games.
So by the end of the second month, I kicked out everyone who didn’t create any giveaways and started thinking of new ways to prevent unwanted individuals from entering the group and to increase the quality of the giveaways.
You can see my first discussion with the community about these matters in the old recruitment thread comments:
https://www.steamgifts.com/discussion/jMqJT/quality-games-giveaways-qgg-group-popular-giveaways#s3CDJEi

With time minimal group quality requirements were refined, monthly requirements were added, basic requirements for newly joining members, and a 7-day without entering any GAs period for new members (to show they can follow the rules before they officially join).
When transgressions in the group became more subtle, I was forced to add our anti-abuse rules, to keep the group fair for everyone.
And we added our bi-yearly special games, to allow for even better giveaways with an even higher chance of winning.
And that’s how our group grew into what it is today.

You can see my thoughts and ideas about the group rules, in this post from late 2017:
https://gtm.steamproxy.vip/groups/QGG-Group/discussions/0/2549465882915464035/