How fuck do i get things downloading more?

I got 49 things in my download list, and a 45 of them are blue, which means there is a source to download from.

So why fuck dont they download

One of two will, but slowly.
Sometimes its rapid, 50kb/min etc, but right now, bollocks all.

Whats the clients on queue thing about?

And with servers, whats PING about? Should it be high or low? Does it matter much?
I just usually connect to whatever server seems to have the most users, as ive not got a fucking clue what its all about