I'm not a pro, but what I find works for me is to use the thinest solder I can find. I heat up the iron, wipe it on a dry cloth (rag), apply a small amount of solder to the tip and use the now melted solder to heat up the wire / pin that I'm working on, rather than the dry tip of the iron.
add a touch more solder, then leave the iron tip on the pin until the solder flows.
now I don't know this bit for sure, but I think if the solder balls up it means that the parts I'm working on didn't get hot enough. melted solder on its own wont do the trick, every thing needs to get hot enough.
the solder I use is real thin, like 0.020 inch or so. maybe less.

again, I'm not a pro. and my work doesn't look as good as most of the stuff I see.

hth