As a fellow newbie DIYer . .I have found the most success with simple recipes - ie - 1 flavor and maybe some menthol or koolada. I don't make tobacco flavors so can't help you much there .. but 2 things I would recommend is longer steeping - my fruit/mint flavor juices seem to need a solid week to come together - before that they just taste wierd. I made a watermelon/lemonade that was god-awful on the second day . . but a week later it's been upgraded to "not good" - but thats a big improvement and at least it is useable, lol.
The second is . .20ml batches?!? I make 5ml test batches and am thinking of cutting that down to 3ml. I am stubborn and will try my best to vape anything I make . . .my second batch ever was 10ml of really gross mint chocolate chip . .got about 3ml left to suffer through. That experience has insprired me to make smaller test batches.
There's so much information on this site it can be overwhelming but the universal principal of Keep It Simple, Stupid . .seems to apply pretty well to e
juice. Happy Mixing!