I've been stuck for months. Maybe tracing another isometric base? I don't even know where to start.
Imagine looking at someone from a 45 degree angle, whilst also 45 degrees above them. You're seeing only the corner of that person. What can you see?

Draw that.

I'm crap at pixels, but drawing is isometric isn't a whole new leap once you understand the angle you're dealing with.
In response to Rushnut
Not much to go by but it's better than nothing so I'll take it. Thanks for the reply.
Depending on how big you want to make your characters will depend on what you should be looking at as a general rule of thumb.

64x Breath of Fire 3 and 4:

32x Final Fantasy 12 Revenant Wings(I think) finalfantasy12revenantwings/

Just study how they do it, don't trace. Say, okay, BOF3 used way more colors than BOF4. Maybe, I want to use more colors. Or maybe I want to use less. Or maybe I don't want them that big. You might want to organize your thoughts on what you want from your base. If you don't know what you want, play around a bit.
In response to Candle_Jack_9000
Great information! Thank you!