I don't know what mods you're running but if they are balanced at all than that means when you have extra traits and ethics so does the AI which thus gives them a buff.
The best way to play this game, imo, is to role-play your empire.
Before game start:
If you are going for a militarist/spiritualist/collectivist empire than first choose either to be an empire or a spiritualist regime, I highly advise not to have any elections as it reduces the annoyance of getting a leader with bad traits (this is my personal opinion, y'all can think differently). Spiritualist regime is imo the best because it reduces ethics divergence, the more divergence the more problems that you will have in the future (especially if you have taken half the galaxy). I didn't see what FTL you use but for a beginner i advise hyperdrive and limit all AI's to this (doesn't affect Fallen though) but it will allow you to bottleneck certain systems with powerful defense stations.
Before you unpause game:
1. Send your military fleet off exploring the local area, I've never split them but I guess it'll help if you run into a hostile alien force. You are looking for good colony worlds, 16 up are my preference, even if its not exactly like your homeworld, i.e. arctic if Tundra.
2. Have your science ship survey homesystem and any place that is already explored, don't want it blowing up from sentient crystals, this will also allow you to find all the resources you will need.
3. Check your homeworld and see what kind of tiles it has, and plan accordingly, I usually try and boost food ASAP as more means more slav...citizens.
4. What you choose to research is your choice but I prefer to try and get shield, ai research, exo-suits, mineral extraction, but for biology always research colony ships ASAP.
5. I also love to switch on the edict for increased research, I turn it off after i get my first colony going (I can't stand it when pops ethics diverge)
Start Game:
It should take 60ish months for colony ships to be researched in this time you can build anything you want until 12 months remaining. At this point asses your mineral gain, because as soon as you research colony ships you'll want to build one, sometimes two if really good worlds are nearby. The rest is almost always personal choice, but here are some tips. Expand aggressively, everything is yours make sure the AI knows it. Use outposts only to keep AI at bay, gain much needed resource systems, and to prep for colonization, personally I hardly use them any more even at the beginning of the game. Absorb as many pre-FTL species as possible, they make for good colonists of worlds you cannot live good on. Usually I purge aliens that live on my preferred worlds but having multiple species in your empire is a real boon. Try an get NAP's with any race you want as a friend ASAP its the best way to get an alliance with them. Oh and remember that after your first colony world is created (2206ish) pirates will show up, make sure you have a fleet of at least 7 and an Admiral for them. Also don't let your influence gain rate drop below 2, you need that to expand.
Hope this helps any.