My past experiences have showed me that when I download files at one time, instead of letting them queue, I double my download speed.
e.g. My connection lets me do 140 to 170 kb/s.
The other day I enabled 120 files to download at once.
And I averaged 300 to 330 kb/s for an hour and a half,
and almost everytime I can double my download speed
by doing this. But I have no idea why this works for me.