You sound like you were where I was at a year or so ago. I've grown a total of 6 MJ plants in my life so I'm a newbie too! I grew up around cannabis though my mom always had Mary Jane growing on our farm. I do grow carnivorous nepenthes, orchids, lotus, rhododendron, fuchsia, veggies, ect..... My seedlings are 2 weeks old. I'm growing Harlequin and Dance World CBD for my personal used as medication for back and kidney disabilities. The one tip I can tell you that has been increasingly useful to me is neem oil! It's a all natural organic Fungicide, insecticide and miteicide in one product. Sometimes Walmart has it in a bottle called
Fungicide 3 by Safe Garden. I spray it mostly on the underside of the leaves but I also add a little to the watering cycle once a week. This helps keep away that powdery mildew that can start on the leaves and buds also helps protect the roots from any kind of fungus. I grow outdoors on the Oregon coast that's a problem for us here.