Hint: Extra Squad Points (Shepherd only)
This Shepherd-only exploit works best when you have at least ten available points. Simultaneously press BLUE (X button) and GREEN (A button) when choosing the fourth rank of an ability.
This bumps up an ability to the next rank (fourth), but keeps any points spent to get there. So for example, if you decide to do this when a rank is at level three, then it would cost 4 points which you would then be given back.
When you do this using all 10 points on an ability, you get all of them back. Free Skill Points!
Note that if you do not press the BLUE and GREEN buttons at the same time you can "Back" out and "Undo Talent Points".
Go to the "Retrain Powers" menu. Retain and max out all powers using the above button exploit. Then go to the "Advanced Training" menu and buy a new power.
It seems that a character can only have seven total powers at one time but you can buy the same power more than once so that a new one over rides an old one.
Go back to the "Retrain Powers" menu and retrain all using the above exploit, again. You will receive at least 50 extra Skill Points. If you up your skills in the "Squad" menu you will NOT get the extra Skill Points.
This process can be repeated for more Skill Points. I went from 45 to 185 in two turns of this procedure. This will cost about 82,000 Element Zero points.
Remember, this only works for Shepard not the other characters, and may be patched in a future update.