I'll post the mistakes I've made or almost made here and update as I make more feel free to respond in kind.
Tip to whisper someone /<name> in chat For example /NakiAse will whisper me though If you don't do it in alliance chat while I am on I'll ignore you no hard feelings.
Resources:
Power
Keep more power than you are using otherwise your build times go up. If you see a build time that is significantly higher than what was stated you may want to use one of your 2 build slots to add power.
By the time I found this out my 45 minute build time was 5 hours...
Colony:
While waiting for expansion culture send probes, don't wait on it, I ended up getting my expansion culture the same day probes started having travel time, Instead of being able to build it immediately had to wait for additional parts.
On the same note Help others (At least in the alliance) to get teh parts that way every opportunity you have.
Questions:
You have a mentor ask any question that you cant find an answer to here, on the FAQ or the wiki. and if you found it but don't understand ask for clarification.
If your mentor isn't on chat works just as well.