For some of us WoW exists entirely within instances. The outdoors is just a lobby where you buy your water and repair your gear.
As you can see from the responses in this thread we seem to be in the minority. The best resource for players like us is a robust and carefully-curated friends list. You want to have a solid core group of like-minded people who play the same hours you do. It took a while for me but at this point I almost never have to resort to LFG or pugging with strangers; I just check my guild and friends list and can throw together a full group for pretty much any dungeon.
Of course it helps to play at peak times. But in general just group as often as you can, and /friend everyone who seems to know their role and isn’t a total jerk. If you can friend enough healers and tanks you’ll eventually have a big enough network that you’ll be able to put together groups easily.
Good luck!