Banish your critic for an hour or so. Gather together: paints, a round brush, water holders, a spritz-y bottle, a rag and a couple of pens. I like microns and the Pentel brush pen.
Watercolor paper will give the best results. It is thick and holds a lot of paint. That's how you get the deeper colors. Well that and courage.
Spritz here and there, then load up a brush and drop some color in the spritzed areas.
Add some more color, drop it into wet areas. Maybe you made mud? Don't drop orange into blue or purple into yellow.
You might want to let things dry (use your heat gun if you want). Then more color
Time to doodle. I like the little lines in the background because they remind me of seed stitch. Try to relax and let go. Think floral rather than "flower."
I think it's more important that your marks have your energy rather than any kind of perfection. Just make marks. Your flowers will be more lively
Have fun. Relax. It's just paint and paper.