Just the usual guitar type things. There is really nothing you can do to mess-up the sound, and it sounds just great.
If it is a "red" special - at that price "customise" the guitar. Make it unique. Punch up a picture of Bri's guitar from the internet.
Remove the old strings. Customise with new strings and set your own action. (The thinner the strings - the better the sound - but they are far less forgiving). A good buff-up with a chamiose and some wood polish should remove any minor scratches or stains.
Remove the "black" plastic protector from the tremolo bar and replace with a white one. (You can use a white plastic protectector from either the top a knitting needle - or buy one from a guitar shop).
If you are good at woodwork - or are near a wood-shop, below the guitar bridge, screw a black plastic "D" scratch plate. (Totally useless - but looks amazing).
Counter-sink a "dime-sized" hole in the head-stock (underneath the BURNS logo) insert/glue an old fashioned UK six-pence coin (or one of the Brian May Tour coins advertised on Queen-online).
Finally, if in a guitar/music shop, you can replace the tonal/volume controls - again to look more like the real thing.
The end product will cost only a few extra quid, but the look is transformed from something approximating Brian's guitar - to an even more stunning replica. The good news is no special skills are required, as they are very simple modifications.
As I said, you can easily find good pictures of the real thing as a guide.
"Listen to them. Children of the night. What music they make."