Geromino: Well the factors are:
- Be the first to act - Alert feat, high Dexterity, Initiative gear...
- Have high amounts of spike damage...
- Have high damage in general....
- Have a lot of attacks, too.
- Inflict conditions...
- Having high crowd control...
- Have as high armor class as possible on all of your characters...
- ...try to get the high ground...; try to attack out of hiding; try to inflict a surprise round...
-... more mobility on the battlefield...
....
To summarize: [1] Act first, [2] deal enormous spike damage on dangerous single targets, [3] crowd control anything you cannot kill before it has time to act
This is a *very well written summary* of what to look for to shape BG3's combat to our hearts' desire!
Here is an example of how I followed those rules/advice as summarized here by @Geromino:
Location: House of Grief, Act 3
Opponents: Boss + 19 minions => a total of 20
Advice [1] Act First:
Three of my party members, who went down for the conversation, took action prior to Boss at the start of the combat.
Advice [2] Deal spike damage:
After conservation with Boss ended in combat, me (Durge) broke Boss' protection, Lae'zel dropped her health down to 40, Shadowheart finished her off. After that, Shadowheart killed 5 opponents, Lae'zel killed 3, Minsc later killed 1, our summons worked together and managed to kill 2 => Total kills in round 1 = 12
Advice [3] Crowd control everything you can't kill:
There were 1+19 opponents, way too many for us to kill in a single round. So, we crowd controlled everyone we couldn't kill. Minsc frightened 1, our summons managed to frighten 1 and stun 1. At the end of round 1, 5 more opponents dashed across the battlefield but couldn't actually get close enough to mount a single attack (because we kept our distance!).
Net result: in less than 2 rounds, we eliminated a total of 20 opponents without giving them any chance to fight us back. Total kills = 20, time = 2 rounds, total hits taken by my party = 0.
Cool, right?
That was in Honor mode, part of my first Honor mode playthrough.
I have been following the same rules/advice/strategies (however you call them), as summarized by @Geromino here, all the time.
In my opinion, @Geromino nailed them.
They are extremely useful, helpful, invaluable advice to follow. In my opinion, any player who follows @Geromino's advice (or whatever is equivalent), tries to fully understand them, and tries to improvise them based on their specific party composition and personal preferences will find every fight in this game just a fun challenge. It will be much less likely to have to make a desperate struggle for survival from time to time, even if playing in Honor mode.
Have fun and enjoy!