Hey, I was wondering if there's any easy way to properly use a .esp file as a master?

I know it is possible to use wrye bash to temporarily esmify the plugin you wish to use as a master, create the patch file which should be dependent on some other .esp, and then afterwards use wrye bash again to espify the original ''master'' so you can still upload your mod in the form of a .esp instead of .esm.

The problem I have with this is that any time I want to slightly tweak one of the patches, I first need to go through the process of esmifying and espifying the ''fake master'' again, and another issue is that it is more complex so other people will also have a harder time making their own patches.

I just double click the .esp (and any masters besides skyrim.esm) so they are selected, and select my mod as the active one.
I routinely do this with hair mods when I am creating NPCs.
If you are asking about merging esp together, then take a look at http://www.creationkit.com/Talk:Mod_Merging for a detailed procedure.

Strange, I've tried this a few times and it doesn't tend to work correctly for me if I do it this way. No I'm not talking about merging btw

As far as I know, there is no way in the CK to make an esp the master of another esp. From what I've read, the game engine can handle it, but the CK doesn't allow it for some reason.

I don't understand why you don't just esmify the esp. If you need to patch it at a later date, your new esp can be patched without having to make make it an esp again. Just use the plugin esp to patch the master.

You'll have to go through the ritual each time unfortunately. The CK will not do patching properly if you don't. It'll likely be quite some time before we see a CK Extender like there is for Oblivion.