I'm the first to admit I'm not a particularly good or confident cook - this is not helped by DH being incredibly proficient in the kitchen!
Some things that have helped me - good cookbooks. I don't see why I should reinvent the wheel, others far better than me have written the recipes, and all I've got to do is follow them!
I've found over here that Hairy Bikers and BBC Good Food are very reliable.
Secondly, it really does help if you have good equipment - good knives (never put them in the dishwasher or cut butter with them, good (and lots of) chopping boards, measuring spoons, cups, jugs and scales.
Thirdly, an awful lot of cooking is just muscle memory, it's a bit like ironing, the more you do, the better you get at it, the more confident and quicker you get. Chopping onions, mincing garlic, peeling, chopping and salting veges, browning meat. . .
Fourthly, and foremostly, if you cock it up, there's always takeout, so don't be afraid to fail.