i loot as i go through an area, even if there's still enemies, i don't kill everything then go back, thats double work, i always have a follower so they watch my back or sometimes are battling while i'm looting, i'll take out my share of enemies then start looting then move on to the next room, building area etc.
My style?
You can call it "the art of fighting, without fighting".
Except I just kill everything and loot afterwards.
First time in a place, thoroughly loot everything, including dead bodies as they fall to the ground. There's time to do that before killing their friends. I'm reasonably methodical inside a room, and over the level, but have been known to miss things. Second time through and after that, I generally just follow the path to the objective, looting on the way, and ignoring side-paths unless I know of a particularly juicy loot site.
Tend to loot as I go but also tend to go back over the site checking in case I've missed anything (unless the site design makes that impossible) once its cleared. Whwn I leave a place there won't be a tin can left unlooted if I can help it.
I pick things up as I go, and I won't return to a location just to finish looting it. Once I've hit my limit, that's it, so I aim to pick up the most useful and valuable items. Other than that, what and how I loot depends on roleplay rules for each of my characters.
My main won't pick stuff up from feral ghouls, and she will never leave behind "Ghoul Slayer" weapons (the only exception to the no looting ferals rule). She does her best to help settlements, so picking up anything that can be used to make life better for settlers is important to her.
Another doesn't care about helping settlers. He just picks up anything that's useful to him, or stuff requested by Brotherhood members. He only collects junk that can be used to fix up armour and weapons.
At this point in my favorite places to go I know where it is what I like to take , so I'll pick those while I go through , from enemies , only their ammo and stimpacks are interesting to get.
Edit: At the start I'll grab everything I can , I remember once getting back to a settlement with 2000+ weight
If it's a new place I'll kill and loot room by room unless I get the 'killing rush' and feel like an uninterrupted raider massacre in which case I'll go back quickly check the bodies for ammo and chems and have a quick scan of each room for magazines or loot I've tagged for search. (Usually adhesive and aluminium for upgrading).
Other than that I don't spend a whole lot of time searching especially if I've been in the place before as it gets boring for me.
I did go back to Hubris comics for Grognak's Axe though as I somehow missed it the first time...
Whatever the place I go to it is kill everything first then loot second. I do it this way so I can take my time looting and not be rushed because some Raider or whatnot is trying to Super Sledge my head off.
It depends. If I can clear from room to room I will. But some zones you have to clear multiple rooms first before you can leisurely loot a room. I stay in stealth most of the time, so if it says "Hidden", that means I'm safe to loot. If it's caution, or danger, I'll keep clearing until it says "Hidden".
Then I loot in a pattern to not miss anything. I stay to the right wall as you would in a maze so you don't miss any rooms. Then loot outside to in of each room. You don't want want to miss any skill up comics or valuable "junk" for crafting like hot plates or toy cars or rocket ships etc...
Kill everything.
Take everything.
If it's a big building then I will pick a Container near the exit and dump all my loot there whenever I get bogged down.
Because, while I like stuff, I hate being bogged down with it. On some of the largest indoor Maps I will have multiple Stashes at the starts of all the Sub-Areas and will just hoover all of them up as I head on out for the last time.
I usually sweep through the area killing everything, looting only the corpses as I go (in case they despawn before I can get back to them), then explore the place afterwards reading terminals and looking for loot and trying to figure out any story the place might have.
I tend to be looking for specific kinds of things and generally limit my looting to whatever I'm looking for.
Now-a-days, I loot as I sneak around. My robot companion usually kills everything while I do so.
I just go room to room, clear the room then loot the room. In more confusing buildings I end up doing some backtracking to make sure I haven't missed anything. Looting and exploring obviously get easier with each playthrough. Once you've figured out the best way to get through a maze of a building, that puzzle is solved forever.
I use mines to watch my back. I block off pathways that I think someone might be patrolling while I nose about in a room. Works rather well... even if they spot the mine and I get a [caution] sign, little red blips show up on my map and I get to know where the enemies are at.