There's not much you can do about jet lag. It's a real drag on recall and dreaming.

As for insomnia, I suffered (and still do occasionally) it after-5-hours wakings a LOT in the beginning of LD practice. I spent a lot of time researching effective ways for me to relax my mind and body.

For one thing, adjust your time spent awake. Experiment with much shorter times up, and even no time up, so-called "micro-WBTB" where you just re-set your intentions and return to sleep.

It takes practice and dedication, but I believe anyone can learn to quiet their mind and relax their body sufficiently enough to return to sleep in a short amount of time. For me, if I can hold my mind absolutely still and focus on the feeling of "letting go," I'll fall asleep pretty quickly. It takes willpower to ignore the thought-chains that beckon to you, tantalizing you to immerse yourself in them and thus stay awake.