ideas?

I have my tree image printed out and I've been sewing it. I'm using bigger thread this time because even when I used different colors of small thread you could still barely see it. I'm using cream colored thread and I'm going to color over it with green pastel. I'm having trouble figuring out how to sew into my landscape with the flowers. I don't like the thicker thread because it's just too visible for me. I'm going to try with the thin thread and see what happens. I think I'm about done with my tree on screen but I'm not sure. any suggestions?