Many communities devote their homepages to showing a list of categories.
Don’t do this.
A member with a burning question should be able to ask in the search bar or click a button to create a question immediately.
Almost no-one randomly browses through an endless list of questions hoping one has the answer.
When people visit they usually need to be able to search, ask a question, or see what’s new and popular in the community. Keep the categories small (like Atlassian does).