This is all about my _own_ efforts learning to TIG well. I had to slow down and not treat it like MIG...
I think I'll always be learning how to weld. Consistent start and stops are important. Heck, it's all important and I'm not qualified to offer advice... Here are some things that I've learned so far.
Create a simple work flow for preparing your practice materials. (like cutting straps or tubes (coping) as a production shop might). Cut/fit everything set it aside and then prepare your workspace. Make sure you are safe and your equipment is in order, then weld until you run out of materials. Everything about welding is consistency and constant improvement. I started my practicing on whatever was laying around, didn't really cut/clean/fit and thought I just sucked... After a while, I started focusing on say round tubing, then sheet metal, etc... I imagined that I was working as a fabricator/bike builder even though I didn't know how to weld like one. It's amazing how fast you will learn if you just put yourself in that mindset. Welding is only a small part of building things. (I digress about my own dreams)
I found that if I rushed to just start welding I rushed through the actual welding itself and had bad starts, stops, and had a hard time with it and never finished well.
Long winded answer from someone who is learning the same as you... Suckback, concavity and porosity are all evil. You can even make it look good on one side (like a motorcycle frame) and have it totally be crap on the other side because you did not add enough filler rod or burn in / move slowly w/ rhythm...
What model TIG are you using?