Pick up a copy of
Self-Editing for Fiction Writers. It's a great book. Can't recommend it enough.
Chuck Wendig's site (terribleminds.com) has a lot of tip posts.
LitReactor has a mess of Chuck Palahniuk articles that are all writing tips.
For what it's worth, here's some of mine...
0. Scenes should "be in a location and feature a character with a goal that is in conflict with another character." Start late and get out early. Start the scene when the conflict starts, end the scene either when the conflict is over or after the character has reacted to the conflict. Don't forget to let your characters react to things, make the decision what to do next, and use that to drive the next scene.
1. Structure is just an escalating chain of cause-and-effect, action-reaction. As long as the words "therefore" or "but" connect one scene to the next, and things get worse for the characters from beginning to end, you should be close enough.
2. Dialogue in novels isn't real world speech. Cut out the boring bits and don't let your characters be too on the nose.
3. Verbs are your friend. Flaccid and placid verbs are death. You don't have to go to the purple side, but verbs carry a lot of weight. Use them well. "He walked to the door" is meh. "He sauntered to the door" is slightly better and adds characterization.
4. Action is the ball in sport. The reader follows it wherever it goes. It's a volleyball, hit from one side to the other, constantly going back and forth. Don't jar the reader by having your characters do lots of stuff without any response from who or what they're acting against. (Cause-and-effect, action-reaction).
5. Default to first person or close third. They're the easiest to do right. Describe what the POV character feels, don't state the emotion they feel. "I was pissed" is kinda bad. "My cheeks flushed and I couldn't help but clench my fists" is terrible prose, but it's better than the first. Conversely, only describe the outward effect of emotion in others, what could be seen on camera.
6. Don't be nice to your characters. They exist solely for you to kick in the teeth. So start kicking.
7. Avoid filter words that distance the reader from the action. Saw, looked, watched, and others focus the reader on the character passively interacting with what's happening. Tighten that by cutting out the filter words. Focus on what's important. "He watched as the fighter crashed" is very different from "The fighter crashed". The first focuses on the character doing the watching, so it should be important, like say someone he cares about is on the fighter. The second focuses on the action. Most of your stuff should tend to be the latter, but the former has its place. Use either when they're called for, but know why you're using one instead of the other.