When I was working on my copper scrollwork pendants, I looked for an efficient way to solder them as there were many elements in one piece. I found a youtube video on pick soldering, and that was exactly the technique I needed. You can find the link to part 1 here.
She uses liquid flux in a needle top bottle, so I bought a couple from ebay - and it works brilliantly. I had been using liquid flux on a paintbrush, but this is so much quicker and less fiddly. Try it!