[Aussie Mike]

You only need the christmas tree technique when going verticle up to provide a shelf to hold the weld pool up. When you go accross just go straight into it, I don't generally weave. Just watch the weld pool and control your speed to make sure it grabs both sides of the join and also gets right into the root of the fillet. On larger fillet welds it's often better to put a root run in and two capping runs on top. That way you get good root penitration which is where the real strength is. That's for heavy materials ie 10mm thick etc.

Cheers

edited for crappy spelling