Ok welcome to the forums vicki!

Dream signs are probably yur best bet, so try doing reality checks throughout the day, and as for those nasty dreams you cannot escape from, well a lot of people often realise it is a dream but dont know how to escape.
If you find you 'cannot escape' then you must realise you are dreaming, just follow up on that and think 'wait a minute, this is MY dream!' then youve got it cracked.
If you find that you cannot bare the ngihtmare any longer, you can just blink repeatedly to wake up, but i would reccomend you just laughing at the nightmare, it sounds corny but if you do, then you wont be afraid of it, and then you can go ahead and whup its ugly beyotch ass.