In new game player settings - select racial points for new player to 5000. Then you can add an empire with 5000 points used. You have to edit the empire and adjust the point balance to zero to play with 2000 or 3000.

I have 239826 racial experience accumulated and am rated "old". I find that the AI is more willing to make treaties and less prone to break them now that I have lots of experience. They know that I will whip their behinds if they start trouble. You get racial experience for building ships and bases. You get 100 experience for every colony you plant. I have not checked what else gives experience, there may be some minor contributions from other things. The fastest way to get experience is to play a big map, make all the AI but one neutral surrender, then colonize all the planets on the map and save your empire. Repeat on another map etc.....

I already posted my empire on another thread. If somebody else has a higher experience then they could post their empire files on this thread for newbies to download. On second thought I will just post mine here too. It may make it easier for you to use mine. Just edit the empires to be whatever you want for your race, and use my experience level.