Appearance: Fender eliminator, flush mounts, windscreens, spools

So... some of the easiest things to do from the start is cosmetic changes. Don't expect to see any performance gains, but do expect to catch some looks. One of the most common changes is getting rid of the bulky fender in back, this goes for any bike to be honest. They are like parachutes. Just look at it.

http://www.machus.net/2009/04/05/turn-signal-intergration-yamaha-yzf-r6-2002/

Plenty of room for a license plate, maybe even a billboard or something. Turn signals stick waaaaay out. And there has to be a bit of a drop and a reflector. There are plenty of fender eliminator kits on-line for $10 or less. Unbolt the stock fender directly from beneath and follow the instructions of the kit (usually bolt it directly where the old one was, unplug old turn signal and plug in new one) they keep it simple:

http://www.xdcycle.com/discount-motorcycle-accessories/Yamaha-c-67/?page=4

What is that, two small pieces of metal bolted together? Simple is sometimes just better. This one also looks like it can even be flipped, no need to bend any license plates. It also comes with turn signals.

Now, you may be wondering, what if it doesn't come with turn signals? Well, two options for that. You can either:
a) buy flush mount lights that hide cables and usually look smooth with rest of body. They replace front and rear turn signals. This may involve taking the tail (or front/side fairing if front) apart and bolting from inside. You may be able to get away with  just taking off the passenger seat.
b) buy an integrated turn signal kit. Less equipment sticking out. $20 kit usually that has adapters connecting turn signals into tail light. So when you put out signal, the tail light will blink on one side.

Windshield can be swapped by unscrewing 6-8 bolts if your going for a tint or the "speed bubble". Tints are fairly cheap($20), but the racing one will start reaching $100. The race bubble will smooth out the wind right above your helmet, compared to having it rush directly into the front of your helmet.

I mentioned getting bike stands in my first post, but your bike will need spools that bolt right onto bike. After they're on, bike stands will pop the bike right up and make work or cleaning soooo much easier. Why bike companies don't just install them at factory, I have no idea. They cost $5-10 at the dealer, make sure to use loc-tite on them, vibration from bike will undo them over time. People tend to get angry when those things just pop off and hit your car (or bike in my case).

I'd say those are top cosmetic changes people tend to make most off the bat. Cheap, much nicer appeal and helps out.