First, I start with W, World Atlas, and 1-2 potions depending on how greedy I am for money.

BASIC BEGINNER KNOWLEDGE
I head to the jungler and follow him if hes doing an invade, using W or flash to get kills or dash out. After I leash, I head to the bottom lane and tell the ADC to get level 2 quickly. Losing level 2 first isn't game changing, but being level 1, sitting behind the ADC and getting poked can be very bad.

EARLY GAME POKE
At level 3, i start to be more aggressive, using bush to poke, or even using bush Q to sneak in, auto them, and sneak out using another bush Q. If you're using electrocute, that is a very good strategy against champions without CC. If you're using first strike, just use bush Q to poke for the gold.

EARLY GAME ALL IN
If you think you can get a kill, go for it. Once you recall, you can buy a partial item hopefully. I recommend getting tiamat second since it isn't as good as lethality, but I would go for it if I can't afford the other item.

ASSASSINATION STARTS
At level 6, poking isn't as needed as before, since a random bush Q barely chunks their health. I usually still poke if my ADC is poking to stack up the damage, and start to look for a kill angle while sitting in the bush.

ROAMING STARTS
After you have destroyed the first turret, it is safe to roam, but check on your turret every once in a while to defend it. If they destroy your turret first. Start to roam since they will most likely defend it and kill you.

HOW TO ROAM
Now this part of the game is mostly just warding the map and farming. I try to push lanes for exp, gold and turrets. I always try to go for kills if champions are by themselves. I make sure they're alone using wards and assassinate them.

HOW TO ASSASSINATE
To decide who you assassinate, always check the leaderboard.
1: Enemies with HEALTH
Enemies who build Health items or shields can be a problem since Qiyana removes armor using lethality.
2: Enemies with ARMOR
Lethality may get rid of armor, but not all of it. So avoid enemies who are tanks since they have both armor and health. ADC's with one item should be fine.
3: Ranged or Assassins.
Ranged Champions are obviously squishy and assassins build damage. Since Qiyana has crazy speed, she can out speed almost every assassin.

Many things in this guide may not make sense since I am not good at league. This guide is just to show on how to play and get fed as Qiyana.