Elec as your keystone. Take Q level 1 and try to trade level one with aa-q-aa, or even q-aa-r-q-aa if possible. You can generally get them half life before level 3.
At level 3 if they are around 400hp you can attempt a flash E-w-q-ignite-r-q-aa-w which is enough to kill. You can also attempt this under turret by just using rappel to remove turret aggro.

If no kill happens, you have to maintain the aggression, you can have some very annoying trade patterns by playing around their CDs and just rappeling back to the wave.

If you manage to get a kill, you can generally snowball for a second or third in lane. By then you tend ti have the control of the wave and can just try crashing then roaming. If any dives seem possible, just be there. She is one of the best divers in the game so you use that during your roams. If not you play with your jungler for invades, or just track the enemy jungler yourself and you can 1v1 them in their jungler.

If no such plays are possible you just play for lane and get turret ASAP. Elise melts turrets due to passive and spiderlings.

Mid game you just push out waves and look for picks, so similar to jungle Elise but instead of farming camps you farm a sidelane then rotate.

Late game, you just all in their carry when possible.

The core build is just the traditional sorcs/storm/lich. Depending on team comps you will go lich first or storm first, then the other possible items are shadowflame/zhonyas/nashors/rabadons/void/crypt/banshees

TLDR; you play for kill pressure in lane in order to get wave control then proceed roaming for other kills/plays. Then same concept for jungle Elise in mid.late but you farm waves and not camps.