Having recently gone through a similar experience with my wife's bike (seldom ridden last year due to law school), I am guessing the carbs are probably all gunked up with crud and varnish. This is bad.
You can try adding lots of carb cleaner to the tank and continuously trying to start it and that might work, but even if it does start, it will be rough running.
I ended up pulling the crabs out of her bike, taking them apart, and cleaning them thoroughly with carb cleaner. While I had them apart over the winter, I ordered a Factory Pro jet kit, installed it and reassembled everything.
Added some fresh gas to the tank, which I had previously drained.
The bike started almost immediately. And it runs significantly better then it ever has. Off the choke in about 30 seconds, and ready to ride away in less time then it takes to get the gloves, jacket, and helmet on. Low end stumble is gone and better mid-range power too.
Gas mileage likely suffers a bit, maybe from 75 mpg to 70mpg, but who cares!? it runs soooo much better. In Canada the bikes are jetted ridiculously lean to pass emissions testing and that really hurts the ridability of these bikes.
I would suggest at the very least you pull the carbs, clean them thoroughly, and adjust the pilot screws as noted elsewhere on this forum. Get a service manual and do it yourself, or a competent mechanic.
And then, if you ride infrequently, make sure you use gas stabiliser all the time, and start the bike up once a week. This keeps fresh fuel in the float bowls and stops the gas from going "stale". Or better yet, ride it more!!!
If it is going to sit for more then a few months, follow the proper long term storage as noted in the manual. You won't regret it.
Hope this helps!https://www.250r.net/forum/images/smilies/smile.gif