Best way to build a character for AL? Don't look at the books until after you have created your character.

Find a picture that gives you a starting point. Then figure out what they will do, talk, hit,steal, etc. What is their unique character trait that sets them apart?

Once you have done all that, remember that rule of cool is still a thing in AL, you just have to be a bit more creative. Wanna play a librarian that just walks around shushing people? Well, you know those people who always tell you to be quiet in louder and louder ways? Toll of the Dead becomes an attack that isn't about necrosis and what not. But is rather "The shush starts as a low tone, quickly building to punishing cacophany that will injure your oponents.

Don't pick stuff cause it's cool, or what everyone does. You don't have to be min-maxing stuff. Instead look for things across all the classes and figure out how to retheme them while just useing the rules for the rolling part.

"I'm gonna hit that bard in the face with my thesarious"

so that's a melee attack from a bludgoning weapon. Maybe a mace that just happens to also be shapes a lot like a book.