From personal experience... don't record at a fast BPM if you want consistency. Also, try to actively remember the tone you want to recreate! It might help. Another idea is to make sure the first sample is in the tone you want, and then you could pause recording every so often to listen to it.
As for avoiding saliva sounds, make sure to stay hydrated! They're common-ish in voicebanks, though, so I don't think people mind them. If you're trying to avoid them because you don't like them, that's another story (and I'd understand that completely).
Training your voice sounds like a great idea, too, so it's good that you've been doing it!
pffff Pazuru just said everything I was going to xD but I'll leave this up anyway, I was almost done typing this when you posted lol