I didn't play through, so correct me if these were changed since 3/NV, but:
If you hold the action/drink button on a source of water, instead of just pressing it and letting go, you'll continue to drink and regain HP (and rads) faster
When hacking a terminal, look for strings of text in between signs, like {j3g4k1} These will remove a fake answer or restore your attempts.
Bosses are immune to the eat command so it won't be possible to end the final boss fight of the game by eating it.
-VeghEsther