If you have engage supp with cc which suits you very well, from level 2 dont be afraid to go trade and spend mana. farm and poke with W and E.... with good supp almost noone cant win level 2 trade with you. if youre on lane with lulu or some poke champ, leave her poking enemies, and engage only if enemies engage on your supp. Like that youre getting really nice W and kill is secured. If in lead go agressive as you can, try to constantly attack from stealth and tilt your enemies.

Farm, Farm and Farm, if enemies started to group you should farm and always try to flank them. Ideal engage time is 3 seconds into the fight, let enemies spend their abilities, and spray them all.... should not engage teamfights without good protection or if core items are not finished... TIP: if enemy team is on Baron/dragon go in jungle, ward the pit, and ult them. Like that youre most times safe cause of distance and wall, and can fully utilize your ult, and maybe even steal the objective

All you need to do here is catch enemies alone, or if grouped flank them after teamfight starts.... do not ever start teamfights....