If I recall correctly here is how I recall it from my play thru split into two characters. In total I spent 383 hours to get all trophies (PS3). Working on Xbox version now mainly for DLCs.
If you already have achievements those are done. You can do factions aka thief's guild, dark brotherhood with different characters. The main story needs to be done in one , however if you have done it you only need to do parts of it to progress the story. To get best Mage you want to do the Winterhold story complete.
NOTE: some of these can glitch and will glitch so save often.
daedric artifacts needs to be done all under one. collect 15 daedric artifacts. 30 points. You need to be level 30 to do some of these (some are lower level) there are 16 both don't rely on that , I did not manage more then 15. Follow the guide in the sticky.
I split my game into two characters , it was on ps3 , however it works the same on Xbox.
is level 50 that takes awhile.
learn 20 shouts takes awhile 40 points
You need 100,000 gold can be easy! 30 points
You need one skill to 100 if you only need a few high then easy- takes awhile. 40 points
clear 50 dungeons level 40
discover 100 locations , I don't think you need to clear them I forget, sorry.
stones 13 of them , unless it is fixed you don't need to find them all as going to them again counts , forget how it worked as I got it and did not see all of the on map.
is main story and take awhile if you have not done it yet! 50 points
so you only need to do some main story ones
Example if you done dark brotherhood achievements then no need to repeat, unless you want to, same with thiefs guild, civil war, companions.
Each factions has 3 achievements so any missing ones you need to complete. You need to however start from square one aka at 1st achievement and get all 3 in new character.
One with the Shadows - 30
can take a long time
Thief - 30
Pick 50 locks and 50 pockets , you need to be a good pickpocket to get this.
Will update above if time permits
NOTE read thru the achievement sticky