tig welding is super easy if you practice and know the tricks. good cuts are the key like emminodagreat said above. however, it is not hard to make a weld across a 1-2mm gap. the trick is to start a weld bead on each side of the gap and place the third bead between the two beads. this works great on aluminum pipe with a big gap because aluminum does not sag that much.

here are some of my tricks for newbies.

-sit on a chair and spread your legs to have a wide base. the extra balance allow you to control the pedal better. this is especially important when letting off the pedal complete because you don't feel like you are going to fell over onto the work piece.

-brace your arms on something

-mover your head to see the weld bead instead of imagining the movement. the first tip above will assist you here too.

-try using your dominant hand to feed the filler rod. this is the most important trick for newbie and even pro.

-make sure the gas is flowing correctly. 15-20cmf is the key number.

-sharpen the tungsten correctly. i find that a flap wheel on a 90 angle gives an excellent finish. sharpen with the grain toward the tip or you will not going to get a good finish.

-use good filler rods. use the smallest rod possible to get the bead size you want. this is very important when welding thin metal. if you use a big filler rod, you will have to stay too long on an area to flatten out the fill. this is ultra important when welding aluminized steel or thin stainless steel to prevent burn through.