Yeah I noticed the swell too....
It's funny, dynamic control kinda just came to me over time, I never really thought of it until now actually. And now that it's come time for me to kinda impart my own knowledge on it (which is actually pretty limited, I would suggest getting advice from Intero or Paradoxphenomena in the art of dynamic control since they're awesome at it), I gotta assess how I do it myself. Hmm....
Well, I guess I'll start with what you want to avoid. Heavy compression is a big no-no. I know a lot of people will tell you that this is a bad idea, but beginners might wanna set the compressor to just eliminate clipping. Then just lower the imput so that only a bit of your song is actually compressed.
Now as for instruments, well your instrument choice will definitely affect how much volume is increased. Flutes playing octaves won't be nearly as loud as trumpets playing chords, you know?
Also, it depends on what you want to express in that particular portion of the song. If you want a certain part of the song to express an explosion of emotion, then have the volume of the instruments raise for that particular section, then let it die down, as you don't wanna keep the song "up there". And dynamics are essential to beginnings and endings too.
Wow, I really suck at giving advice on dynamics. I guess it's best to show by example than by the written word, you know? Well, luckily I know of some songs that are excellent examples of great dynamic control. Listen to these songs:
Paradoxphenomena- Silent Night
Intero- The Menace
Danman87- Entering the Stronghold (well, that song's just amazingly amazing all around)
Brokendeck- NBTB: Soundtrack Version
Blacknote- Both his Mac9 entry and his Mac8 entries are good examples.
Plus you could just turn to your local classical station to hear some actual dynamics, cuz what's better than hearing real instruments?
Well, that sums up my advice. Yeah, I know it sucked, but I tried, and the road to hell is paved with good intentions. Wait a minute....