I know I am probably expected to give you many titillating stories, but instead I am going to be boring and direct you to sources instead. Sorry internet! But won't it be so much more rewarding when you get to see these accounts first hand!

There are tons of primary sources that depict sieges and battles and that might give you some idea, though keep in mind many of them are written by clerical figures who may or may not have actually been present and who are probably "livening" things up.

Some translated works you might check out include:

Abbo of Saint-Germain's "Siege of Paris" (Bella Parisiacae Urbis). Depicting the 885 siege of Paris by Vikings this is technically early medieval, not high, but it gives you a sense for the way authors presented sieges. It is arguably highly embroidered, there are lots of conversations, interactions that the writer couldn't possibly have observed, and a lot of the technological terms and ideas are drawn from Roman writers and don't necessarily accurately portray the nature of early medieval warfare. Still, it is a rip roaring good time, lots of sallies, arrows, ambushes, etc.

Fulcher of Chartre's Chronicle of the First Crusade is a solid source, some of which is even primary, on the crusades which might be useful given its description of the initial capture of Jerusalem, and the siege at Acre and other major battles. Many of the source books that contain this will also have selections from the numerous other accounts of the crusades.

Jean Froissart's Chronicle is later still, depiciting numerous encounters during the Hundred Years' War. Lots of sieges, and a decent eye-witness nature to much of it. Froissart is pretty keyed in to the life of a knight and the nature of military engagement.

You might also seek out some troubadour poetry (Bertran de Born in particular has some interesting martial poems) for a less "historical" approach. There are bunches of collections of translated troubadour poetry.

So yeah, lots of primary sources for you to check out, Penguin editions etc.

There are also quite a few secondary sources that may help, check out WorldCat a major library search engine.

For instance, The Medieval City Under Siege edited by Ivy A. Corfis and Michael Wolf has a whole bunch of articles you might find interesting. I'm sure you can find a whole bunch more sources on siege that might in turn lead you to even more primary sources (though not all will be translated probably).

Hope that helps!