In no particular order...
Be specific - sardines being grilled is better than fish being cooked.
Use active and direct verbs - he walked rather than he was walking.
Avoid abstractions - such as horrible, violent, frustration.
Make every scene and sentence count.
Use the minimum amount of magic/hi-tech to get things moving.
Adverbs - Gah, away with them.
Reveal character by action. Put characters in situations that force a response.
Do not hide information. A surprise works better if no-one suspects it is coming.
Experts plan to the end.
Dialogue - Do not let it meander. Conversations are great ways to show character and attitude.
Elaboration of motive - a character's actions should reveal more about them, what they are doing and why they are doing it.
Write for yourself and no-one else.
Writers write - try to make progress every day.
Keep an ideas notebook with you at all times.