Oh, man... Wow. That's a...heavy compliment. I am hardly a master though. Still learning.
I use a TON of references. For every betta, I go and find multiple pictures. Hunt down all the photos of the fish that have been posted. Search pictures of other fish for anatomical correctness (I'm horrible with proportions, so it won't be perfect, but it is still a hundred times better than what it would be without something to look at) if I'm using other poses.
When I start a drawing, I sketch an outline in pencil first. Figure out the angles and lines. No details at this stage. Here's an example, using the drawing I'm working on now (it is the "No-No's", aka Skyewillow's cats, No-More and No-Less). Ignore the wonky limbs--I took that picture in the first draft to see if Skye would like the poses, before I made the corrections. When I'm lazy, I skip this step. I also don't usually do this for my tribal pieces.
Next comes the inking. I do the eyes, scales, and basically all the details during this phase. Only one chance to get this part right because I am using pen. If I mess up, I scrap the entire drawing and start over. Most of my drawings take two or three redos because I get really hung up on minor details. I am a perfectionist too.
Colouring is one of my weakness, so it goes however it goes. I spend a lot of time picking the right colour. If you give me a blue fish, I'm going to use multiple shades of blue. I use black and white a lot. I find that everything looks better with shading and highlighting.
After all of that, I still find flaws that irk me. But I don't redo after I complete the colouring. Each drawing takes me about an hour and a half to two hours. I colouring really slowly.
Sometimes, I don't bother with the planning and being careful. Then, you get pieces like this (super messy).
So, um, yeah. That's that. Feel free to ask all the questions you want. I don't mind one bit. I just can't guarantee I have all the answers.