mate of mine has a 1.2 clio and he loves my 182, so luckily we found a 172 in the local breakers and took some of the sport bits and pieces off it - gear knob insert, dash inserts, side sills, some interior bits and bobs, the Renault sport sill plates and we were thinking of taking the wings and front bumper off of it too! spent about 75 quid in total and he is really pleased with it all!
other than that i would say upgrade some of the speakers if you plan on having an aux connected or your own music on, definitely upgrade the bulbs (interior, dipped/main/fog lights, licence plate, indicator and side lights) if you can and if you really want to, get some cheap lowering springs and a splitter!
window tinting is a good idea too, as well as making sure it is all clean and polished and waxed etc but tbh do what makes you happy and what you want to.
unless you have a sport or something with a turbo there is very little point in doing any 'performance' mods haha!