This is quite an easy first project to get you started machine patchworking. I prefer the 'homemade' quality of items so I don't meticulously measure and cut the fabric but if you want to it would be best to make a paper template and cut out the fabric with a craft knife but it's totally personal preference. Also colour schemes are a personal thing, you could match it to the room it's going in or just use scraps that you've got available; I went for green fabrics and yellows but a good guide is use the same thread for everything and if the thread looks really out of place on one bit of fabric, it probably isn't working in the colour scheme but that's also up to you how you choose your colours. :)
Firstly, you'll need to measure your chosen cushion and decide how many patches to make; for me I thought it was easy to measure 4 rows of 4 but you can do any number of patches :) then cut them out and work out the positioning of the final piece.
To join the patches first join the rows, when cutting the patches out allow a seam allowance and then draw round the template of your final patch size on the wrong side of the fabric- I used a pencil but you could use tailor's chalk
Line up the patches right sides together and pin in place
Sew down the line that you drew earlier on the wrong side of the fabric; this prevents any raw edges. This is why you can draw in pencil because it gets covered by thread later on.
When you've joined a row of patches, it should look like this
When you've done all the rows, press them either with an iron or because it's a small project I used GHD straighteners
Join the rows in the same way you joined the original patches; then add a ribbon trimming or other decorative features to your taste
Cut a piece of backing fabric to the same size as your finished patchwork square; then hem it and pin the 2 pieces together right sides together and sew up 3 of the sides
Add a fastening; I used velcro but you could use snap fasteners or buttons or you could add the cushion and sew up all sides
Turn your cushion cover right way out and add your cushion. Step back and enjoy! xx