Lanaya can solo mid well, due to refraction, which allows her to stay longer in the lane and meld due to its high bonus damage and - armor you should also get bottle for early game and rune whore.
How to gank:
If u have dagger use refraction then blink, try to get close towards your attack range, if you didn't just try to get closer then use meld then, use your ultimate as close as your enemy then activate it then just keep attacking, you may blink again and use meld and your ulti.
Well if you don't have it yet just plant a trap, or activate a trap that is already in range of the enemy, then activate refraction, make sure you know her attack range, just try to get as close as possible while activating meld then attack and just use whatever skill you have like mentioned before.
Item build in order (core):
Well thats what I usually buy, you may change some of the items such as having travels and mkb etc.
As for skill build 1 lvl of psi blades and max meld and then skill refraction whenever possible