Tips from a truly terrible baker who has dramatically improved with lots of recent practice (I often make cake/biscuits for 70-100 people over the course of a week - amazing how doing it lots really helps!) Tonight's special was carrot cake cupcakes with cream cheese and orange icing, by the way.
Make sure your ingredients are at room temperature before you start.
Always measure as accurately as you can.
Don't improvise until you know what you are doing.
Be aware of how your oven cooks - I ruined many many cakes over the years by cooking them 20 degrees too hot.
Cook it in the right size and shape tin - that really can make a difference.
Get some fool-proof recipes. I've only ever had one of Mary Berry's recipes fail on me but loads of Nigella's, much as I love her I like it when the instructions are as exact and idiotproof as 'beat for 2 minutes' becausr I never know when I have mixed things well enough or too well.
Concentrate at first - I've made lots of mistakes by trying to multi-task, so set the timer for the oven a few minutes early and check. Cakes are usually cooked when they bounce back when you press them.
Watch a friend who knows what they are doing while they make a cake and ask them why they do things - best way to learn.
Good luck! Few things give me as much pleasure now as being on my own in the kitchen baking, whereas I was so awful before that I used to cry at my cake disasters.