What to upgrade?

First I want to say I am pretty new to warlock, my skills are not the best but I now atleast got a combo to use.

The thing(my question) that I wonder most is what to upgrade to what lvl first, should I get any item(exept boots of speed), shall I upgrade lifedrain, aoe, range or just aim for skills upgrade.

My main skills are fireball(ofc), lightning, fire spray, teleport, shield and wind walk

Sometimes I ofc try to mix with others and stuff but this is my main skills and those I think I work best and so I wonder how I shall spend my money after I got all these in lvl 1.
And just hopefully to make it easier base your opinions that I get 10 gold after each round with League B mode

1. There aren't any bad skills. A skill is good as you play.

2. Nobody can say what you should upgrade. Play with them and try out which you think are the most effective upgrades. (take skills you want/like to play)

3. You will see which build you make. (You'll see what your opponent takes and can vary your build)

Hmm makes sense, I guess you are right:) thanks for the advice