Hey there, hope I can answer a few things here for you. Here goes.

The techniques in which you wake up are called "Wake-Back-To-Bed" or WBTB. You can combine WBTB with another method in order to increase your chances of having a lucid dream on a specific night.

HOWEVER, not everyone likes this and in this case your alternatives are Reality Checking and self-affirmations. If you can make an effective habit out of Reality checking, and reminding yourself before bed that you 'will check reality and remember you are dreaming' (for example)....then you may have a good chance of becoming lucid. It may take longer to get used to, but you will have some success.

You may not have a specific dream sign (i dont think I do either), but you can reality check anyway. You have to constantly watch out for "strange things". Something unusual happening near you? See something new? Check reality! Its about watching for things that arent normal. You dont need specific dream sign to do this.

Sounds like you had a lucid dream...but got excited and woke up instantly. This is normal for your first few tries. look in the 'dream control' forum section for tips on staying in the dream.

I find that CONSTANTLY watching for unusual things throughout the day is HARDER than trying WBTB techniques. I wake up after 5-6 hours....go to the bathroom and then go straight back to bed. This means I lose almost no sleep, so it doesnt make me tired. That said WBTB techniques are more complex, and reality checking is much more simple. (having said all this, reality checking is important to ALL lucid techniques because without it...how do you know when you are dreaming?)

Hope this helps you out!