My first issue was rabbits. Rabbits were feeding on my freshly planted tomato sprouts. I solved this problem by sticking a plastic fork next to the plant, a suggestion I saw on the internet…seemed silly, but it worked.
Next my plant was putting out flowers, but only a few of them created tomatoes. Back to the internet and I find that if it is hot, humid and little wind, the flowers will not self-pollinate. You need to shake the plant periodically to get the pollen flowing, kind of like jerking-off your tomato flowers. Gross, but it worked and soon I had dozens of tomatoes weighting down my plant.