I have a problem in FLS9, id like you guys to help me.

Some instruments i have, like sweeps, boobass reduce a lot the volume of other instruments, especially hats, kicks, snares and sytrus. Can i do something about that to prevent it? Is the only solution just raising the volume of the intruments less listened from others?

Raising volume is a common mistake , Use FL's EQ (there are 3 i think!?) use the one that you are most comfortable with to boost the sounds you want to hear more of for example - You said boobass reduces a lot of volume on other instruments wich im taking that your using BB for your bassline ? Reduce some low end and boost up your snare's , HH , Same with any other instrument you  wich to hear more of . EQ'ing is probably the most important thing in making a track so is  using  you'r ears as well whatever sounds good is good! Just keep practicing with your EQ skills and your music will sound more 'Professional' 

I tend to gradually reduce the volume of all the instruments. For one thing, it'll help your final mix and you'll have a ton of headroom for mastering. You should want to mix at a low overall volume, so it's good practice to lower the volume on sounds that are too loud to clear out room for other sounds. One thing you could try is to set a baseline volume, be it your kick or some other key instrument. Then lower the volume all the way on the other instruments. Gradually pull the mixing volume up on each element until you get a sound that sounds "just right."