how to reach Diamond I, step by step.

1. pick fizz
2. start with your Q, once u reach level 2, level up your E next and you are ready to begin.
3. Q into your enemy, then use E.
4. Did he die? if the answer is no, repeat step 3. if the answer is yes, continue collecting all the free farm. Using your Q allows you to poke your enemy to death, and using your E guarantees you won't take damage. It even misses turret shots even though one of the turrets "abilities" says turret shots cannot be dodge.
5. continue doing step 3 until you reach level 6. one you reach level 6, farming will be easier than ever. Ult your enemy, doesn't matter if he is turret hugging because you can just E out of tower range without taking a SINGLE hit. If your ult hits, Q into your enemy then use your E. At this time you should be carrying your team and nothing will be able to stop you.

p.s even if your ult doesn't hit, you can just tower dive with your Q+E combo. that should suffice.