There is a server near me in Mississippi that is packed, 44/44, nearly all day and night. I'll tell you how this server runs.
Late night/ Early mornings are on a dust2/office rotation. Later in the day, it is a constant vote map and we play random cool maps, some that I haven't ever played and some that I haven't played in a long time. Either way, the maps are voted for and we finish the current map then play the following map in its entirety. I stress this because I cannot stand it when I am in mid rush, five rounds into office and reach a loading screen because the admin wants to go back to dust2. I think letting maps play out and finish is very important and EXTENDING maps is equally as frustrating to me. Lets extend dust2 for thirty minutes, we'll keep the same shit teams and dish out 16K and all is well in the world. Half the time there isn't a vote for the extension either.
They allow custom skins which I am not per say a fan of, but a lot of people that keep returning to the server have skins and it pleases them. I think they also have bots when it gets to a certain low amount of players. I know some people are very against bots, but if having bots shows 10/32 when people search for a server, well its obviously a lot better than it saying 0/32 all damn day until 7 PM.
Final thoughts:
-noblock good
-skins may help
-bots may help
-let maps play out
-having more admins and active members WILL HELP.