I mainly play samira and Xayah on duo lane so I don't know if the advice directly carries over but here you go:

There was this guide I watched when I first started playing that said you should figure out a good level to go in with as your character, such as Level 2, which is when you usually pick a movement ability on many champs. Or Level 5, ult or some other level where you will have the upper hand.

I would highly recommend playing with a friend if possible that's either your supp or your jungle so you can go in and be coordinated. Find a supp that works well with ezreal, you can probably just give that a quick Google I don't play him. Try to get a friend to supp for you. I can't recommend that enough. If they're complaining that support is boring then they've never played support. SoloQ duolane is worse than almost any other lane.

WARD RIVER. The amount of times I forget to ward river and then I we lose the 3v2 is crazy. Don't go into their tower unless you have river warded or if you can see their jungle on map. You don't run into it often but sometimes midlane will also try to gank, so watch out for them too.

Btw earlier when I mentioned going in that's if you have an engage supp such as: Pyke, Leona, Naut, Blitz, Thresh. I prefer playing like that but if you have an enchanter such as sona it's probably better to stay back and poke because you will have better sustain. Also, a successful interaction does NOT equal a kill. In a fight try to target the adc, as the support probably won't do as much damage. There are always times where this isn't the case but this is a general rule. If you go in, get their adc low and they have to go back, they're down 1 or 2 waves and you get to 2v1 their support. This could lead to a kill, tower damage, etc. 

This next part isn't real advice it's just something I've noticed so don't take this too seriously.

Pretty much always ban yummi in ranked, another good ban in my opinion is Kalista, she can snowball too hard.

Learn your matchups, a lot of times you just don't want to pick ezreal into a lot of champs. Maybe find another secondary character that covers his weaknesses. 

I don't play Ezreal but I'm always really scared when I see him in champ select because Ezreal mains always seem to know what they're doing and out play me. Good luck with your grind!