The key to mastering any skill is knowing what to do when it does go wrong, and the great thing about soldering brass is that you can always undo it, clean and retry.
Though some days it pays to stop modelling and do something else before it all goes to hell in a handcart.
The other morning I sat down and soldered on the cab spectacles prior to fixing the cab front on the footplate. Really neat job with no excess solder.to clean off. Presented it to the footplate and realised I'd soldered them on the inside
Wisely took my wife shopping instead.......