ok i always see that people max E first or second...i play different. (im not saying its better)
for me is R>W>Q>E
the first thing u need to know is how to play in teamfights, u dont initiate, always wait for the other/s to atack and then go and take the kill .
now, from the beginning: start with W, try to last hit minions if u can, it will be really hard the first 3 levels, especially if the enemy is agressive. Once u reach lvl 3, W+Q the enemy and then use E to fall back. U can do that like 2 times and u will run ou tof mana, anyway the enemy will retreat a little so u will be able to farm better.
With doran rings (i always buy 2) u will not have mana problems, so start being moree agressive if u see that u can kill the enemy. If u can't, then just farm until lvl 6, once in lvl 6 if the enemy's health is 75% or lower, u can easily kill it with ur combo (W+Q+R+ignite+ E(if necessary) )
in my build i always buy rabbadon first, then lich bane (i tried only once lich bane first and i didnt like it, but many people does, so, do whatever u want)
ok thats how i play, i win mid lane like 85% of times. Fizz counters almost all the mages so dont give up to him, its a champion that requires a lot of practice.