Divinity: Original Sin
Have a party member with high Perception.
Hunting for tiny buttons on 3D landscape is the devs idea of an 'old-school puzzle' (of which there are many), so be prepared for that. High Perception lets you spot things easier and makes it a bit less of a chore.
The world may seem open but it's actually structured in a way that you're strongly encouraged to do the areas in a fixed order.
There's no point torturing yourself trying to beat level 7 mobs while you're level 4 since there's probably a spot full of level 4 mobs that you've just missed. The challenge of taking on high level mobs isn't worth the reward of becoming over-leveled and turning the otherwise moderately challenging encounters into trash combat.
Try things that look fun.
Enjoy the challenge while it lasts. The game's best part is the first area when you're still weak. Don't worry about spending gold on things in it, you'll be swimming in it soon enough with nothing good to spend it on. Your couple will turn into unstoppable juggernauts no matter what you do. That said, if you really want to make it easier for the first couple of areas, bringing a mage is a good idea. AoE spells wreck the early-mid game, melee fighters wreck late game.
Get Teleport immediately.
Aside from it being useful and hilarious at times, it tends to knock people down, which is one of the ways you can do some crowd control (freeze/shock/knockdown) where that enemy basically can't do anything and may be extra vulnerable.