You just keep trying and talking to the folks here and figuring out what works best for YOU. I started another celery stem a few weeks ago and it's got 5 inch new sprouts. I have it in a quart canning jar with 3 inches of water and sitting in the south, sunny, kitchen window. THIS one might make it, but the others I tried dried out.
Another thing, sellers tell you to do "recommended" things that really just make you buy more of the same. I am not putting 3-5 seeds in each cell when I start tomatoes later this month. I can never figure out which ones to snip and which ones to keep. Besides, you end up with younger and older annual vegetables in your garden anyway, so why not just put one seed in the cell, and if it lives then it's easier to up pot?
The other thing is your lifestyle. First year I've had inside basil. I cheated and bought the plant, BUT, I put it in the guest room west window, just off of the kitchen, where it's easy for ME to water and retrieve. Good thing the only houseplants upstairs are geraniums bc they love drying out. I don't go upstairs every day, so I neglect them. Just super soak them about once a month.
IMHO, regarding starting seeds inside, you should adopt the idea of "keep it small", and then you'll probably be more successful.
