Don't spray with the MP5 ? It's the best spraying gun in the game ! Of course, over long distance, you better burst fire, but short and middle distance, spray is still going to hit pretty good.
P-90 ? If you want to play seriously, don't even buy that gun.
Same for para. (It can be pretty accurate, though, if you use single shots. Bursting with that gun is not recommended either, because it gets unaccurate too quick, even with small bursts of fire. The first shot, however, always hits the crosshair's middle, and if that shot is a headshot, it will always kill.)
AK-47, you never want to spray with that gun, only pointblank, as Lancer said.
M4A1 is a little better there, the spraying distance is better than the AK-47's.
Sometimes, spraying is just too tempting. Your job is to modify that sometimes, you only want to spray when you have a good chance of hitting with that gun you have there.
Also, the UMP 45 is a great gun alternative, because it's got this "man-stopping-effect", which means that if you hit your target, it will be slowed down considerably, even more so than with other guns (almost complete stop), which makes it alot easier to land further hits.