How do you guys do sieges as a melee-heavy faction?

Melee heavy factions as in Nurgle, Khorne, Greenskins, Beastmen, Slaanesh, Tzeentch, Norsca and more.

So how do you approach sieges?

Do you avoid climbing walls?

Do you blob your melee infantries and have your high mass units or fliers go after key targets? (I do this as Nurgle, cuz of the heals, but idk whether to do this with other melee-heavy factions)