You have to have a VERY steady hand. You make leetle tiny circles, moving from the "old" puddle to the unmelted area, so you are making a puddle that is solidifying on the tail end, and melting on the leading edge. It's like you are making a series of multi overlapping cursive e's, sort of like looking at a spring at an angle.

It's useful to be able to use the off hand to steady the hand with the torch in it, which is why welders have lots of clamps and those really nifty right angle magnet jigs, so you don't have to hold the work and weld too. And why a grinder is your friend. A good grinder hides a multitude of bead fubars...

And practice, practice, practice, and cut some welds so you can see if you are getting good penetration, the key to a strong weld. And get the Haynes welding manual...