Well - I'm filled with trepidation now.
Someone mentioned masking and sanding the joins (which never occurred to me) and then I found a website (Hyperscale) that shows some incredible paint jobs on models...several of which I have and whilst I wouldn't expect my paint jobs to turn out like theirs, I am now very disappointed with my work :-(
These are photos of an Academy Ju87 (the top images of each pair are Chris Wauchop's work I found at Hyperscale - THEY ARE NOT MINE! - the top one of each pair is Chris Wauchop's and next images of each pair are mine (mine are the crap looking ones!)- and to think I was quite pleased with the result on my version!
*edited above to be clear. I don't want people thinking I'm taking images of their work and pretending it's mine
I mean - a whole different league. I just asked my wife if I could look at getting a small compressor and airbrush set and she said "No - that's nerdy!" - mmm. Support for ones hobby is always welcome. To be fair though, even I'm not sure I would have the patience to go to anywhere near the lengths that these people go to. I have shaky hands and not great eyesight which makes detail stuff quite difficult.
Anyway - if anyone has good tips or knows a website with good tips for making and painting, I'd be very interested - I'd love to find out some techniques - especially for brush painting as it seems unlikely I'd ever go to spray painting - though I do love the effect.