Doing pedal kicks after and endo is great, that's how a lot of riders begin to learn how to get on their rear wheels, but what you really want to learn is how to kick your front wheel up with a "pedal punch" instead. Before trying to add distance and altitude to your pedal kicks, try getting to rear wheel without doing the endo. Instead give the bike a little pedal kick while leaning back and lifting your bars up. You definitely want to get your basics down well, so that you don't develop bad habits later on.
To answer your question though, when most riders start out they're pretty stiff on their bikes. (especially when balancing on the rear wheel) So what you'll want to do is get comfy on rear, that way you can maximize the power you're putting into your bike. If you feel solid on your bike, you'll have a good solid base to jump from, and if you have a solid base to jump from, you'll be able to jump off of it harder. So as a general tip, I'd say as you learn to balance on your rear wheel, try letting your front wheel down a bit and lean forward just before you launch if you want to add distance. A little tip...keep your elbows bent
The best advice I give to a new guy for adding altitude to any move is "preload". Generally that is the first thing I see new guys lacking in. A tip for this one is to keep your knee's bent, and don't be afraid to move your butt around the bike.
Here's a good vid that shows what I just explained.
Notice how he leans in before gaping, and how low his preload is.
The best advice anyone can give you though is JUST RIDE Some days you'll want to practice and get better, but don't forget to mess around and have fun also, that's how you'll find your own style as a rider.