Hi there,
First of all, you shouldn’t blame yourself, becoming lucid is a proccess which you prepare your mind, so sometimes it may take a bit till you discover the right way your body works.
Anyways, don’t focus too much on having one LD just follow the techniques.
When trying WILD do it after 5 hours of sleep, when you’re in REM state, it’s a lot easier. Lay down, relax all your muscles, I mean feel that happening, being relaxed. Then focus on your breathing, doing it slowly and deeply till you feel really confortable. So numbness will start slowly and if everything goes all right you’ll feel SP.
There’s no exactly time to SP starts, just let your body relax as you would while in sleeping proccess.
Here’s a great post that you/everyone should read, it’s really inspiring and has a great concept. Stop trying to dream