Vertical Welding Question

So in class we did a little vertical fillet welding, bottom to top, arc welding, 6013 rods, IIRC. Anyhoo, I got pretty good at it, except that I have hell establishing a puddle at the bottom without it falling out a time or two. I asked the teacher (well, a sub) and all he did was tell me to preheat my rod by holding the arc a little long for a bit after striking it. I'm pretty sure I was doing that anyway, since I made a habit of it, but I went and tried anyhow, no change. How to get a puddle established when welding up? Another question, possibly related: Sitting and thinking, I believe my technique might have been wrong, after I got a puddle going, even if I did get a good weld out of it. I had my rod pointed upwards into the weld just a little, maybe 10 degrees or so. Is that correct, or was I supposed to lean it the other way? Pointing it down into the weld would be more consistent with the way I hold it when welding flat. And would that be the source of my starting problem? Spring break now, so can't play anymore for a couple of weeks. Damn vacation!