I recently redid our couch pillows, and sewed kitchen cushions for all of our dining room chairs. Unfortunately, I didn’t take pictures of each step, but here is how I made them. For the couch pillows, I redid one side so the other was still the couch material. All you have to do is sew the sides that you want facing out facing in (hopefully that makes sense), turn it inside out, and then stuff and hand sew it closed!
The chair cushions were similar but I over stuffed them and then sewed little buttons on them. I added another little personal touch by crocheting the “straps” that tie the pillow to the chair.
As for the outside pillows, I used an outdoor table cloth! They have held up nicely.
You can find instructions at your local sewing store for things like this. I winged it, which is why they definitely look home made J