Typically, you want to 3 camp into gank.

This is achieved through RED -> BLUE -> GROMP

or BLUE -> GROMP -> RED

then you gank a lane for prio into a double skuttle

you can maybe look for a 4 camps (Just include wolves in both 3 camps) if you feel like you can't gank any lane.

Please dive, this is Elise's strongest point of a champion and why you pick her.

Repel not only makes you invulnerable but also drops agro meaning you can simply not care about turrets most of the time. If you have spiders, when you land from your e, they'll tank the turret. Look for stacked waves against turrets and near 75% and lower enemies all the time when playing Elise

Your W, Skittering Frenzy is an Auto attack reset, use it right after an auto attack

You can E, Repel to Plants (Honey fruit, blast cone, scrying orb) for crafty escapes

When securing or stealing an objective combo your spider q with smite to deal tons of burst damage (Your Q typically does 300-400 damage to objectives so aim for 300-400 damage above smite for a good secure)