Hello all,
I'm still a rookie and this model kit thing

but here's a few things I've found:
1) Glueing painted parts - if you can, scrape away the paint from the area to be glued on each part first. Then use your regular model cement. If you don't want to do that, you'll have to use super glue and the join will literally be the painted coats only. Not very sturdy at all.
2) Painting order. As I've built more and more kits, I've found that assembling as much as possible before painting is the way to go. If you're brushpainting, it might not make as much difference as I painted and built as I went. When I started using spray cans, I found that getting as much of an assembly completed worked much better.
I recently picked up an Iwata Revolution CR airbush and Iwata PowerJet compressor, and I have to say, I can now see how the experts can build an entire kit then paint it and get into the nooks and crannies. You have so much more control over paint flow and direction with the airbrush and it literally seems to find them all on its own (or so it seems).
3) Airbrushes & compressors. I'm not sure what they'll cost in Europe, but the Iwata CR was $65 shipped here in the US. The compressor was expensive at $400 shipped, but I like it. There's a bunch of options. For me, I find that the Iwata CR, as my very first AB, is very easy to use and pretty simple to clean. I haven't done a full kit with it yet, but in my experimentation, I'm confident that I can paint my next one fine. The compressor is the tough part. I personally needed something that ran very quietly as alot of my modeling is late at night. I also wanted something with a tank so it wouldn't run constantly. I paid a premium for a hobby compressor, but it made the most sense to me. You may be able to just use a general purpose compressor that's much cheaper, but louder. Just keep in mind you'll need to have water/moisture trap and regulator added (most likely).
Hope that helps!
- Frank