really the best way to go about it is dig through a couple of your favorite logs and take notes like judgetstone said but ill drop some basic pointers

you have to be funny
despite popular belief this part is not optional

and dont just quote weak tweets you saw two years back that made you briefly exhale hot air out of your nostrils

its not like you need to be a professional standup comedian or anything just have a basic grasp on non-referential humor

as long as your log doesnt look like it could pass for an incorrect-hs-quotes post on tumblr four years ago youre probably in the green here

"no caps or punctuation" also isnt an actual rule and everyone who tells you that is setting you up to fail

he uses both every now and then for emphasis or when hes particularly emotive or even just for readability so dont be afraid to pop a couple question marks every now and then

a decent amount of dave rambles boil down to taking a simple metaphor and grotesquely expanding on it
so its a good idea to familiarize yourself with some common idioms both to use normally and to build off of

also theres zero shame in having a thesaurus on hand if you feel like your verbiage isnt colorful enough

gaudygleeman put it a bit differently than i would but seriously just dont think about it too hard

there is an incredibly thin line between making dave look like hes trying way too hard and making yourself look like youre trying way too hard and believe me when i say you do not want to cross it

monologuing or swearing or referencing his interests or using slang too often is just gonna make you look like a complete and utter tool

which i guess is kind of the point but just dont go totally overboard with it

ive hired a hitman to plant a pipe bomb in your computer wired to explode whenever you utter the words "obama" "apple juice" or "karkles"

good luck