Simple, strong solutions for both:

Half-Elf:
-Give them a +2 to any ability score of their choosing and a -2 to another of their choice, representing their versatility. Alternatively, give them the human skill points.
-Their choice of proficiency with one of the following: longsword, rapier, longbow, or shortbow. Representing their elven heritage.

Half-orc: Drop one of the negative modifiers, representing their Orc heritage. Half-orcs now start with the Toughness feat at level 1, representing their Orc heritage.

You've now made them equal-ish to the other core non-human races.