another tip is if your using cubase is too send certain sounds too the same group bus..so if you want a phat sounding bass add 2 or 3 vsts too the same group channel and add a bit of chorus or distortion or whatever fx you want too make it sound thick as possible.
then the same goes for your pads ,group those together and add a good reverb but not too much ..then for the lead just go crazy use a few more lead type sounds group them together then goto each
vst channel and start panning each one around so when they lead sound kicks in it will sound massive.
also dont forget too use compression to stop some sounds over powering the others ..
youve got some excellent vsts too start with and theres no way they should sound flat ..if after what tips weve gave you there still sounding flat then check your amp or eq you may have knocked your high end down.