Not much information to go on here. Do you need privacy? Shade? A windbreak? Do you live where it gets cold in the winter? Do you use this space year round?

Do you need an eating/grilling area? Multiple seating for large family or guests? Picnic table? More room for kid stuff like toys or trike riding? Lounging furniture for sunbathing? Room for a fire pit, hot tub, kids wading pool?

Are you considering enlarging the space? Do you like gardening and are thinking of planting things around the patio? Do you have dogs that use the area for a potty and for exercise?

Do you have a budget or is the sky the limit?

Your patio needs a sense of enclosure, so you could put low bushes or planting beds around the outside, and maybe a tree that will grow big enough to give it some shade if you don't plan on a roof. It also needs color: choose one or two colors for bright cushions, ceramic pot(s), and flowers. You are starting with a blank slate, so this is a great opportunity!

I’d move the seating area you have now over and put the settee under the window. You could anchor it with an outdoor rug and pillows. Outside the door area I would put a small round table with chairs. On the table I’d put a pot with seasonal flowers or greenery with a solar light placed in it. (I’d also add a solar lantern/lanterns on your other table in the seating area) If you get a table with a hole in the center you can add an umbrella in the warmer months.

Yes, should you consider making the patio larger? I think there are many possibilities. If you have a larger budget.

I'd focus on the lawn. Get it looking great and anything you do on or around the patio will be icing on the cake!