Countering mass archers

I'm talking mainly as Bulgarians, whose skirmishers aren't very good. I don't know how to counter massed up archer, especially when they are combined with paladins/halbs. Even worse than this is cavalry archers (mainly unique cavalry archers like camel archers and mangudai which absolutely mow down my armies. So how should I approach this as bulgarians. I try to use mangonels but often they are able to snipe them before i get within range.