Another site with a great starting guide to lucidity is Lucidipedia. It contains very detailed information on how to do everything (using the WBTB technique as a basis for beginners), including lots of tips on how to stabilize and make the most out of your dreams, plus exercises you can do when you're awake, etc. It's quite a lot to read on there, plus a good amount of YouTube videos. I'm nearly done reading everything from the "Learning" section now, and I feel like I know a lot more now than when I just browsed random short articles and guides (although, ofc, I'm too new to tell if it's working yet). It only took me a few days to have the first, short but vivid, LD.

Also, if you are getting frustrated it can be easy to start beating yourself up over it. Try to never think "how did I miss that dream sign? I'm useless", or "why am I so bad at [stabilizing, flying, whatever", but rather how you are actually good enough, and that you will do it better the next time you have a chance

A quick tip to stabilize and make the dream more vivid when you're already LDing is to rub your hands together for a few seconds. Everything should start to clear up.