First of all, do not install mods that you do not know how to use.
Do not merge them (Otherwise, you may get errors.) not all mods can be merged
Download the fixes of the game itself (At least uslep)
Download (And follow the instructions.) https://www.nexusmods.com/skyrim/mods/72725/ And set "UseOSAllocators=1" and "AlignHeapAllocate=1" (It will help prevent crash (And help against crashes in general) when racemenu sliders update (sam body sliders). And you will see which mod is needed to others mod to work) in CrashFixPlugin.ini
If you have a weak processor (or whole pc), then do not install many mods in which there are many heavy scripts (or do not install them at all)
See instructions in what order should the mods in the launcher...
Drop SKSE.ini (which I shared below) in Skyrim/data/skse folder. It will help too ._.