I used to be a disaster in the kitchen - zero knowledge, confidence or ability in the kitchen. So these tips are from the perspective of someone who knows how intimidating the idea of cooking can be.
30-minute meals are mostly lies. If you're not an experienced cook you won't be doing the processes at top speed. And a lot of them are just taglines to sell a book, and conveniently omit time-consuming preparation like chopping a million vegetables. There's often hidden work in the ingredients list ("two onions, finely chopped") as well as the actual recipe.
Prepare everything beforehand. Start thinking about what you're going to cook in advance and leave yourself enough time to get the ingredients at your leisure rather than rushing out at the last minute. Before you start cooking, get all the pots, bowls and implements you're going to use out and clear enough space so you can use them properly. Then you can follow the recipe smoothly and avoid hurdles like "oh shit I don't have a pot big enough, wtf will I do".
Know your limits. Different people have different weaknesses in the kitchen. For me it's embarrassingly basic - I can't chop. No knife skills and I like having all my fingers. So any recipe that requires finely chopped ingredients is out. I choose recipes where I can get away with roughly hacked onions (which is actually most of them).
Cook with someone who's good at it, if you can. I've essentially become an adequate cook through hanging out with DP in the kitchen, doing things like weighing and washing up but also picking up his techniques and knowhow.
The more you cook the more you'll develop your own knowhow - once you've done a recipe a couple of times it's surprising how quickly you feel you can own it and tweak it.
For a cookbook that's both brilliantly written, easy to use and follow for those on a budget or with limited equipment, and full of varied recipes that are both interesting and without exception delicious, I can't recommend Ruby Tandoh's Flavour highly enough.