#1 mistake for new growers is lovin yo plants too much, if you just gave em some water once in a while and had good lighting then the soil should provide everything it needs for at least the whole veg part. But instead peeps like to check their plant all the time, thinking "hey if a lil nutrients are good, more would be even better" and they water it too much cuz one leaf looked a little bit sad. then they nute it again cuz the leaves are starting to go yellow and brown from the last over nuteing, but they think its a sign of starving. anyways the main point I am trying to make is just give a soil grow water and light, thats all mother nature gives and she does an excellent job.
BTW FWIW Years ago I did my first grow with soil, and I made the same mistakes you did and pretty much killed the first plant, it yielded like 3 grams total. my second soil grow I really thought I knew what I was doing and mixed up my own using MG time release. the results weren't pretty to say the least. My third grow I got spidermites so bad the bud was unsmokeable. 4th grow i got spidermites again and had temp problems due to summer time, actually got almost 10 grams off that plant. 5th grow using a soil i mixed that really had hardly anything in it except topsoil and perlite, wow it grew awesome and I got 3 females and actually made enough to smoke for a while. then I started experimenting with Hydro and DWC in particular and found I could grow plants 2 times the size in the same amount of time, but it took some learning there also..but by then Overgrow.com was up and running and I learned a whole lot from some of those old growers that its not even funny. now my partner and I can get 1-2 pounds every 8 weeks, but it took years of mistakes to get here.
You will get there too, don't give up the fight!!