panzermacht

In most games its easy to kill three minions, rush to camp and get xp for all three minions, pick up buff, and come back for the xp of 1-3 minions depending on how fast you where. this is mainly to help you reach level 2 as quickly as possible.
It is possible to return from mana buff and get Totem of Ku before the enemy does following this method.

I have very rarely managed to run out of mana so don't worry about it. Although, if your jungler neglects your buff you are going to have a very hard time.

You will be noticably stronger after stone cutting sword. at this point you would be strong enough to box and win most matchups.

if your opponent is magical you will need to make changes at your own discretion, none of my starting items where very effective against magical damage.

Upgrading order doesn't have to be followed strictly, just start with your second ability, go for 1/3 depending on the situation and put most points into your 2 for waveclear.

dmbrandon also has a slightly outdated guide on his youtube channel, its worth the watch if you actually want to play her.