Musical contrasts can be a great device to write exciting music. Music that puts contrasts next to each other like soft/loud, low/high, solo/tutti, complex/simple etc. can feel very exciting and lively.
However, there are two things to keep in mind: First of all, like every “special effect”, the more often you do it the less impact it will have. A lot of contemporary classical music uses extreme contrasts quite often resulting in an overload and detachment by the listener. So in general, try to not overdo these contrasts, as with every musical device there’s a tasteful amount of how often to use it.
The second thing to consider is to be confident about the contrasts that you’re writing. Either go for contrast or go for transition but avoid having anything “half baked” that doesn’t really feel as if it knows what it is. Make conscious decisions where it should go and score it accordingly. Also note that contrasts on several levels (e.g. going from a loud high tutti to a low soft solistic sound) can increase the dramatic impact.