Ellski

Make sure there isnt anything actually on the wipers or the wind screen like stuff that falls from trees, that will cause patches/smears. Secondly use some house hold window cleaner or some type of degreaser and wipe the blades down, sometimes mine builds up with grease so it wont go over the screen without making that annoying noise and smears everything everywhere. If you do get new blades, make sure they are like bosch or something. I bought a rear wiper off ebay and got rid of it after the first drive because it missed half the screen lol. You could also buy some Rain-X too, that wa

Use a hair dryer to warm up the glue so you can split the plastic lense from the headlight unit. I think theres a guide on here like Yorkshire said but just make sure you use something strong to reseal it back together e.g. tigerseal