Go to professions are generally engineering for the helm, trinkets and tinkers you can apply to your belt/cloak; and Inscription for a 7 int 5 verse shoulder enchant, only requires notherend inscription level 25 I believe? The inscription states 7 int 5 spirit, but as spirit is obsolete it converts to verse.
Best flask for you is
https://www.wowhead.com/item=13511/flask-of-distilled-wisdom or
https://www.wowhead.com/spell=17637/flask-of-supreme-power
These can be quite expensive so another option is to go with alchemy, the
https://www.wowhead.com/spell=105617/alchemists-flask gives you a solid 23 intellect at level 60, you can replace the 7int 5 vers inscription enchant with 7 stamina.
But for Min/Maxing a toon, inscription is best.
Alchemy imo is the one to go if you're cheap and like to hop in/out of dungeons while you world pvp, dungeons strip your flask from your buffs for some reason.
Gear improvements depend on what your goal is. If it's for 1v1's and world pvp you want to stack up on versatility and probably pick a defensive trinket.
https://www.wowhead.com/item=24365/deft-handguards?bonus=4105
https://www.wowhead.com/item=11810/force-of-will
https://www.wowhead.com/item=43664/manual-of-clouds /
https://www.wowhead.com/item=13353/book-of-the-dead
My warlock is geared for a lot of verse so check out the other pieces we can share. Ring, neck etc.
For straight dps I believe that intellect is the go to for all casters at 60 but I've seen some haste specs do really well.
Mobs at 60 die too quickly to get a full rotation going tbh, even bosses - for casters that is, warriors on the other hand finish dungeons on 1-2k dps overall
I would stress that shadowlands is closing in very quickly, when your level squishes you'll be level 24 i believe?
Pretty sure the brackets will be 10 levels at a time still, so you won't even be near to top of the bracket.
The hope we'll even get to pvp in battlegrounds is also wishful thinking at best.
[doublepost=1601627952,1601627667][/doublepost]Probs worth dropping this in as there are some special gems you get, the thread goes into more detail on how to obtain them:
https://xpoff.com/threads/60-warlock-twinking.93607/#post-1234782