This is my Ezreal guide which usually works for me. This is my first guide so light criticism would be nice. I enjoy building Ezreal AD over AP but it is a matter of preference.

Pros:
2 Second Nuke spell
A good escape/ Chase
Scales really well

Cons:
Hard to play since it relies completely on Skill shots.

You should NOT auto attack minions at all since you can not risk being ganked if you overextend.
You should focus on last hitting. Do not be afraid of using your Q to farm since your mana regen is high enough for spamming. Your ult is a last resort farm incase there are too many enemy minions and they are pushing your tower. Also your ult can be used to save towers from across the map. Your Q will quickly reduce its cooldown as long as you hit.

Ezreal along with most carries relies heavily on the team. Your ult can be used to initiate a fight or snipe people after a fight. You should constantly be moving to position yourself to land your skill shots. Use your Arcane Shift to position yourself. Remember to stay behind your teammates as you are squishy. Also constantly use your W not for its damage(which is minuscule since you are AD) but to slow down enemy attack speed and buff your allies. When pushing towers, you can use your W on allies to boost their attack speed but to activate your passive.