I cover my windows. I have made shades of outdoor fabric with mylar sandwiched in-between for some west facing french doors. I took the before and after temperatures: 120 before, 81 after. For a west facing kitchen window, I got a nice big cardboard box, flattened and doubled it, wrapped the edges in gaffers tape and it hides behind my 2 inch shades-ugly but effective. I just made covers for DS and DD's windows, I used an insulating liner curtain, sewed some white plastic rings on the corners, pounded in a couple of roofing nails in the walls. I have a linen shade (mylar center) for the west facing bathroom window, again plastic rings and command hooks--works fabulously-has for years. I have a (one) plantation shutter for a west facing window, that looks the nicest, keeps the room cool, but I'm too cheap to buy any more.
I did replace my south facing windows with spendy triple pane windows, great for the winter, but they still get super warm in the summer. I bought 1 inch cellular shades which work pretty good. The problem with the new windows is that they are too thick for plantation shutters to fit well.