The bike's in storage at the moment due to the snow and ice on the road.  However, when i was riding during the summer and fall, i noticed that the bike got pretty bad mileage.  Everything on her is stock.  I do most of my riding in the city so im usually cruising around on second and third gear at around 30-40mph.  Riding like that, i get around 35mpg give or take.  

Is there anyway to improve my mileage?

how much do you weigh?  I'm like 240lbs which is over half the weight of the bike I"m sure that hurts my mileage.. working on losing about 50lbs...

Also try a fairing, retuning your carb, make sure there are no gas leaks, replace belt with a chain overdrive, new spark plug, new low viscosity oil, lower rolling resistance tires.

I can get better than 49 MPG, but I have to not smile as much.

I think it depends on how often you ride too.  If its a 30 mile commute to work every day thats 60mi round trip and 300mi a week.  The difference between 35 and 55 mpg is 8.5galons vs 5.5gaa difference of 3 ga or about 9$ a week or 500$ a year in gas.  However if you only put a few thousand miles a year on your bike it would be closer to 57 ga form 2000mi a year(40mi per week) and 36 ga a 21 ga difference over a year costing 60$ more a year or a bit more than 1$ a week.  

Its also interesting to note that looking at it as a weekly or yearly cost based on miles traveled the difference between say 10 and 20mpg in money savings is greater than that between 20 and 40mpg.  If you drive 20k mi a year 10mpg costs 6,000$ at 20mpg it costs 3000$ and 40mpg costs 1500$.   Note that you save 3000$ by going from a 10mpg car to a 20mpg car, but only save 1500$ by going from 20mpg to 40mpg.

The very first thing I would do is check to make sure the air filter is clean, as a blocked/dirty filter will richen your mixture and reduce the miles you get per gallon.
That is a simple/quick/cheap thing to do.

As mentioned above then, carb mixture would be the next suspect.
But if it is running very rich there will probably be evidence in the sooted up spark plug and sooted exhaust pipe. If those look normal then the mixture and airfilter are probably not at fault and I dont think you should start adjusting. (That said carb adjustments are straight forward if you have the manual and ideally also a vacume guage). Note: if you decide you want to adjust the carb mixture then make sure you do value adjustment and new plug first.

Incorrect valve adjustment can of course also contribute to performance and your MPG as mentioned.

Poor spark can also contribute. This would be evident from a wet plug and perhaps an easy indicator of an electrics problem being the culprit may be low voltage at the battery when running. But just check you have the correct plug fitted and if its suspect then its real cheap to replace it.

Simple stuff like lookiing for carb float overflow and associated heavy petrol smell (and drips) from the carb, would be another place to look. (Heh also make sure your coke isnt still partially on or something!)

So then if still nothing obvious from above, look at accelerating a little slower..and using a quality cleaner higher octane fuel.
BTW I definitely would not reccommend coasting down hills to save petrol.
Yes, you may well use less petrol, but you have far less control over your bike and its better to spend a few more bucks on petrol than spend a few months in hospital..
(Note..you would fail your bike test if they see you coasting.. and that is for good reason).

But as we agree there are many things that can contribute to poor MPG, so if you what to get the very best out of your bike then you need to address them all..
(Even low tyre pressure contributes to unneccessary extra fuel consumption!).

Push it!

If you dont give it a chance to loaf along in high gear, you wont be getting 45 MPG. Engine rotations vs rear wheel rotations determine it. Coupled with aggressive riding style, yea, gonna get crummy MPG.
Max MPG is at the lowest speed the engine is running freely( not lugging) in 5th gear.

Put a taller rear tire on it, so youll be goin downhill everywhere ya go.
Otta be good for a few MPG, wouldntchyathink?