Two things need to be in place before you can get an alliance:

1. Both you and the race you wish to ally with need the Alliance tech
2. You need Close relation with the race you wish to ally with

So, sell/give that tech to your soon-to-be buddies. After that, check what is affecting your relations with them and tweak anything you can tweak.

Don't have a bigger military than them and you got a - for mil score? Build a few fleets until you get a ++ for military.

Ethical alignment giving you a - and haven't learned xeno ethics...get xeno ethics and match their's (sometimes picking neutral will be best to gain both the good/evil races to your side).

"They know what you are doing" pull that military away from their planets.

Influence/border too close woes...don't know what to tell you there. Blow up some of your planets that are infringing on them?

Just upping your military and getting a few trade routes and a researc/econ treaty with them will be enough to top them off at Close.