So, I play adc, but for the life of me I do not understand what im supposed to do with Sivir 
or Tristana 
. It seems like every other adc is better than them, but when I play against them they seem to at least remain relevant. Any tips for a low elo scrub like me?
If you are new to adc, I would recommend 2 guys-
The only problem with the 2 is, you gota watch your positioning, but otherwise they are the easiest adc's to have an impact with in a game.
tristana is like the best adc lol
I am very bad at sivir, but the area she shines is wave clear. With a few items and some set up, you can use ricochet and a Q to clear entire waves almost instantly. Then late game, her ricochet's ability to crit makes her a menace in teamfights as they bounce around critting the whole team instead of just a single target like most other adcs. The utility in her ult speed up can be great for teamwide engages or escapes. Meanwhile her spellshield makes her safe if you've got the reflexes for it, as you can completely nullify most ults and stop cc.
Sivir isn't really very good until she gets at least 3 items. Her whole kit revolves on getting ricochet crits on everyone in a team fight and then using her ult so her team can chase low health enemies. Sivir is one of those champs where you just farm your ass off and wait for you item power spikes.
Tristana isn't in a very good place right now. Late game she can be a monster if she's decently fed but getting there is pretty difficult. Tristana's team fighting is all about how you use your rocket jump. You can play Tristana much more aggressive than other ADCS because if she gets a kill or assist it refunds the cooldown on her rocket jump. Good Tristanas will rocket jump forward to secure kills and then repeatedly use their rocket jump to reposition in the team fight and clean up kills while simultaneously staying away from threats that can kill them. It's a real delicate balance.
Sivir is more like an AD Caster. I believe she has the shortest AA range among Marksmen. Usually after picking up Static Shiv, I can one shot entire waves. Since her attacks bounce, you always attack whatever is closest to you. Tank, minion, whatever. There's nothing in her kit that encourages 1 v 1 fighting.
I enjoy playing Tristana because she can burst down Towers so fast. Because of that, I prefer to be the last person to join a fight. Having a Trist survive a team fight is almost guaranteeing a tower or dragon goes down. She doesn't feel like a strong duelist at any stage of the game, though she does have excellent clean up tools with W resets. This is mostly because her E is delayed and her R is better for peel than engage.
The fact that neither of these are duelists could be an issue with the present META. Just keep that in mind when playing them. You don't want 1 v 1 or random picks with these two.
