There are many ways to build the energy of a song. One popular way is to incorporate white noise sweeps where a low or bandpass filter sweeps up the frequencies creating a rising effect. This is very much overused and can sound bad if done wrong.
I have made a video to demonstrate the use of automation on your effects to create a more subtle and creative way of doing this. By modulating parts of the synths and vocals (or any instrument) you can have these effects without adding more tracks for samples.
The video, first of all, shows an increasing FM parameter on a synth which brightens it up as it increases, this can be compared to the white noise sweeps as in both, upper harmonics and frequencies are emphasised. Be careful with this as it can add a lot to the volume of the synth, potentially leading it to clip and so you will see the VST Loudmax, a limiter plugin used on it to tame the sudden volume increase.
It then goes on to show an increasing ping-pong delay which can build tension and density of sound. If you look at many builds, the kick starts repeating at decreasing intervals, filling the song with more and more energy. Using a delay like this does it in a much less obvious way. It may not work for all tracks - many may warrant the heavy increasing kick.
When combined with the final formant adjust, the delay will add to the upward sweep of the music. By adjusting the formant, it sounds like the voice is getting pitched up even though it is staying in key. This is because it is essentially shifting the resonances (equivalent to shrinking the singers vocal tract) making it seem higher pitched. If this is confusing, consider a man and a woman singing the same note, even though they are singing that note at the same frequency, the man's voice sounds deeper. This is because the formants would be lower.
For more, see Creative Uses of Common Effects: Reverb to add more intensity to the build up!