Well for a new bike, it's totally a messed up one. However,
1. For the fuel average, get its carb's fuel adjustment settings done properly.
2. This type of gear issue mostly happens when the chain is loose or when the clutch settings are messed up, get it checked, and if it is a chain issue get it tightened, and if it's a clutch issue, get it adjusted too.
3. For handle vibrations, get your whole bike's body nuts and bolts tightened and get your spokes checked if they are aligned or not
4. And lastly for the misfire, there can be two things, either your bike has some missing issue which is mostly due to a faulty carb or it is miss firing because your CDI unit is loose. This miss-firing issue recently occurred in my 2012 Super Power 70 and after checking, its CDI unit got loose, which caused the backfires from the silencer, so I got it fixed by readjusting the CDI back to its position and getting it properly clipped
One more thing after getting 1000 km on the clock get its oil changed and properly tuned for better performance and efficiency. Although, for now, you can try these solutions as I have given above.
