.First you try and try to get in a faction but they say no cause they think your a noob.I can help you with that.

You need to get a full set of diamond or iron armor.That way thy dont think your a noob.Then you should suck up to them;be nice even if its a mean faction admin.They will also apreciate when you go on mining expeditions with them.Be there spoter,protecter,and anything else they deem nececary.With all that you should be not only the mod of the faction you will be the faction admins favorite member. :)