I've done it recently.

Prepare for restarting a lot, Karaman has a lotta issues early on, one of them being a garbage ruler and heir and another one being alliance webs screwing you over.

You should try to focus on expanding into dulkadir and AQ as soon as possible to get a border with the orthodox nations. Try to vassalize some of them to get the force limit/total troop count up. AQ often allies the ottomans meaning that you need to find an opportunity to attack them without the ottomans joining/ attack one of AQs allies.

Ally the mamluks and wallachia for the first war and attack the ottomans every time they are engaged in a war on the balkan side, focus on sieges and try to avoid battles at all cost. Don't give wallachia any land, but keep the mamluks around.