Its always very hard to diagnose nitro engine problems over the internet. There are a hundred different factors that may be causing your difficulties. The best thing to do by far is to enlist some local help. Starting on your own in nitro is often frustrating (it was for me, I had nobody to turn to and like most, I melted my first engine). When all else fails, return the needles to factory settings and try again. Also, just because the glow plug glows, doesn't mean it is good. You should have a stock of glow plugs anyway, because they can go at any time. If you don't have another one you can try, you should definitely get one, at least in order to rule that out and in order to have a spare in the future. Make sure the glow igniter is charged or is a fresh battery, and ideally is a good quality rechargeable battery (GP for example) rather than a standard energiser or something like that, as these non-rechargeable standard batteries are pretty weak, a good rechargeable will give you a much better glow.

As a newbie, you should not be looking for air leaks on your own, identifying those accurately requires experience, as well as solving them. If you have one you will definitely need help to identify and fix it.

I realise this post wasn't much help, but as I say, nitro diagnosis over the net is near impossible. I really strongly suggest you try to find some local help. Good luck.