When I am teaching Go to beginners up to 15k players, I stick with these three basic principles.
More specifically:
1. Tactics: always read at least two moves deep. Do not assume that your opponent will not answer. If your move is only a good move if he doesn't answer, it is a bad move.
2. Technique: If after your opponent's answer your group has less liberties than before, then reconsider your move.
3. Strategy: what's the meaning of stones?
4. Strategy: When looking for a move, look for the largest open area