If I want to install a patch for a mod do I just drag the Meshes/Textures/esp files into Oblivion's data folder? How about if the original mod that requires a patch has been installed as an OMOD, do I do it differently? Can I turn a patch into an "OMOD" in OBMM?

I also want to know how to apply a mod patch through obmm. I'm trying to run the Curse of Hircine Resurrected mod and the only way I could get it to load correctly was with obmm. There is an update to the mod and I want to be able to load that as well through obmm.

You can install a patch mod just like any other mod; either convert it to OMOD for OBMM, or install through BAIN, or install manually by copying meshes/textures folders and esp's to your Data folder.

Just make sure you use BOSS to sort your load order properly, as patches must load after the mod (or mods) it's changing.

Do you mean patch, or mod? And what version of the game do you have?

Thanks. When I try and create an OMOD only the .esp's show up, I figure you're supposed to add the meshes/textures into Oblivion's Data folder manually?

No. A correctly created OMOD will install everything to its proper place.