I have had a passion for fashion all my life and love clothes. I am very diverse in style so here are a few options. Keep in mind that wearing flip flops, sandals or flats with no panty hose is common because of the climate (sunny and warm Florida).
Last Sunday I wore a black pencil skirt, a white cap sleeve tee shirt and a Coral knit blazer) blazer flats. The blazer was more for fashion and to warm the chill when the air conditioning is cool yet removeable when it is warmer.
Sunday before we had a FLorida cold snap (ok 65 degrees) but a good excuse to bring on the embroidered prairie skirt with some cool boots, a tee shirt and suede jacket (same layering idea). The cap sleeve tees are a layering staple.
A typical warmer day is prairie skirts with cap sleeve tees or shirts/blouses and sandals or flip flops. Again this is more of a regional look that would not likely be as common up north.
Experiment with putting together things you have with a few basics. If it conceals garments it's all good.
I'm more of a fan of putting separates together than dresses, but a sleeveless or sundress can be made church worthy with a variety of cute shrugs over them.