Stick down DnD on AoE pulls (and even single-target) as a pre-emptive strike for threat, do this as you're opening in on the target.

For glyphs you want Death Strike, Rune Strike and Heart Strike (Prime Glyphs) on single-target, swap out Rune Strike for the Death and Decay glyph on AoE fights. Good Major Glyphs would be Blood Boil for AoE, Rune Tap (helps healers), Vampiric Blood, and Anti-Magic Shell. Dancing Rune Weapon glyph is rather meh.

For the skills to use: DnD on pull. Then you basically just spam Death Strike and Rune Strike. Heart Strike and Blood Boil are good for AoE (Heart Strike has a cleave effect) and I never use Death Coil unless the target's out of range. Diseases are optional and I only generally keep them up on bosses or with Outbreak only as the damage is rather pitiful on anything else.

I'd suggest you tank normals, to begin with, as well. Even if you've got the tank gear to do Heroics you'll still want some practice in normal dungeons until you've got some practice.

This article on WoW Insider might help you, one thing you'll want to learn (nobody can teach you this) is situational awareness. Watch where mobs are and what they're doing, watch any AoE damage (AMS is handy for this) and also watch your own threat and the threat of other players.