I would definitely suggest using the built-in custom template feature (here's a link to an excellent tutorial). But sometimes you want to save notes and snippets that are not in template format.
For those situations, you could create a code snippet solution. Within that, create projects on specific topics. Then, you can add individual database scripts to those projects.
Here is an example. One project is named Queries. It contains .sql files named Select.sql, NestedSelect.sql, and so on. It may also contain text files under the Miscellaneous folder.
Other projects might be named InsertUpdate, StoredProcedures, CreateDatabase and so on.
An alternative is to use another tool such as OneNote or my personal favorite InfoSelect. I have megabytes of SQL scripts on my laptop in InfoSelect.