Fighters get 4 feats(Levels 4,6,8,12)
Rogues get 4 feats(Levels 4,8,10,12)
Everyone loves a 20 main-stat but the difference between 20 and 18 is only 5% greater success so if a feat is important enough an 18 might be good enough. (8th Level is very far away in playing time so what you choose at 4th level needs to be impactful)
Elemental Adept can be exceedingly important if your mage is focusing on a single element.(Draconic Sorcerers)
Resilient Constitution is important for Wizards and Clerics and Druids and Warlocks.
War Caster is great for all spell-casters.
Alert is fantastic for non-evocation mages.
Crossbow Expert, if it applies to spells as it does in 5e, is great for Warlocks.
A single dip in fighter feels great for a Wizard once you are level 6, but is less fun to play through levels 1-5.
Fighters often take the Crossbow expert/Sharpshooter combo or PAM/Power attack/Sentinel trifecta but if you can find powerful weapons Dual Wielder can be appealing as well.
Lucky is a powerful feat if you can find room for it.
These decisions are tougher without a digital BG3 Player's Handbook because multi-classing is difficult to optimize if you don't know what higher level options you are giving up.(There are lots of class options that don't translate to a computer game so until we know how Larian has changed these features it is difficult to make any concrete decisions)
My first character will probably be single classed for that reason. (I'm one of those weird folks who plans their entire character out before starting playing) Once Fextralife or WolfhartFPS has all the class data on their site I'll be able to make better decisions regarding multi-class.
