I don’t have an alarm, I’m more used to waking up to either natural sounds, my dog waking me up at 5am or cars. I haven’t really seen a convenient method without having to wake up.
If needed I can provide information to help find out if there is an ideal method 
Frequent RCs are probably a great help.
You could try MILD or autosuggestion, or maybe even WILD when going to bed (the last method isn’t exactly easy).
If the problem however is that you don’t have an alarm, just try telling yourself to wake up at night when falling asleep, with a mantra like “In 4 hours I’ll wake up”, it can work very well. 
And you need a very positive attitude for having LD while performing these methods that doesn’t required waking up, so you will have a bigger chance to have a LD eventually.
Hope you can succeed.
But that’s perfect for you. If dog or car can wake you up then it’s just perfect. I was never a fan of alarm, it just to rough when it comes to waking up and then dreaming later on. You way of waking up is very natural, I would suggest when let’s say dog wakes you up just take in what happened:
“Ok, the dog just woke me up. It’s 5 o’clock. I could drink some water. Sip Sip! Ok, now back to bed. Dreams, here I come!!!”
Something like that. Very easy and relaxing situation. Once when you are back in bed you will feel much more mentally awake but your body is still asleep and you can easily fall back asleep but you might have lucid dream along the way…
Doing this you simply raise your chances to have LD’s. This are simple, normal and the most important natural situations, use them… 
Good luck! 