amazingchestahead: First, whether you're playing the original games or the enhanced games, I would recommend that you install the "trilogy" mod, which merges BG1 and BG2 and expansions into one game. This way, you only have to go through the mod installation process once.
The *optimal* order to install mods can be tricky to determine, because, depending on which components you're installing and which ones you're skipping, and how picky you are, some mods would need to be installed in several steps at different times during the installation. For the mods I listed, the general order can be as follows:
1. ToBEx - not needed if you're playing the EE games
2. Ascension
3. Oversight - the "Tougher Sendai" component should be installed here, but everything else later. However, if you're not going to use this component (because SCS has its own version of "Tougher Sendai"), you can skip this.
4. BG2 Fixpack
5. 1PP - only the Core stuff and Improved Projectile Effects
6. Item Revisions - core component only
I'm copypasting here suggested installation order between 1PP and Item Revisions (from IR's readme):
Install Before IR's Main Component:
[101]. Core Paperdolls (included in IR but required for other 1PP components)
[400]. Core Updates and Item Patches (partially included in IR but required for other 1PP components)
[401]. Improved Projectile Effects
Install After IR's Main Component:
[113]. Smart Avatar & Armour Switching
[210]. Increased Paperdoll Object Variety (core)
Install in Any Order:
[102]. Extended Palette Entries
[104]. GUI Additions for BGII
[105]. Avatar Fixes
[106]. Female Dwarves
[110]. Thieves Galore
[114]. Softer Spell Effects
[201]. Consistent Spell and Scroll Icons
[202]. Spell Tweaks
[209]. Attachable Wings (core)
[300]. Fixed Animations for Solars and Elementals
[301]. Miscellaneous Content Fixes
Don't Install Because They're Already Included:
[203]. Restored Flame Sword Animations
[204]. Colourable Quarterstaves
[205]. Legacy Shields v2
[206]. Additional Shield Animations (core)
[207]. Wizards' Staves (core)
[208]. Additional Helmet Animations (core)
7. Spell Revisions
8. BG1 Unfinished Business
9. Revised Battles
10, BG2 Unfinished Business
11. Wheels of Prophecy
12. P&P Celestials
13. Tweaks Anthology
14. 1PP - most other stuff, except Spell Tweaks
15. Oversight - second step, which involves everything else aside from "Tougher Sendai"
16. Rogue Rebalancing - first half, up to "Upgradeable equipment"
17. Item Revisions - other components
18. Wizard Slayer Rebalancing
19. Infinity Animations
20. 1PP - Spell Tweaks
21. Refinements
22. Stratagems
23. Rogue Rebalancing - second half (last four components, starting from Revised Thievery)
24. aTweaks
25. Generalized Biffing - this should always be the last step after all other mods
Mod installation for the BG games can be a real maze and it gets worse really fast as you add more mods to your installation. I highly recommend that you download the Big World Project pdf guide for reference purpose. If you're installing the "trilogy" mod, there are a few other trilogy-related mods that you may want to check out, such as BGT Tweaks Pack, BGT Music, BGT World Map, etc. Again, you should refer to the BWP guide for the installation order of these mods. The guide explains exactly why certain components have to be installed before or after certain other components.