Here is what I do. I add the dependencies to my pom.xml and run mvn. I then get an error about the missing dependencies along with the full command needed to register the JAR files in my local repository. I enter those commands, the JARs go into the local repository and then I run mvn again and everything compiles.
The easy part is coming up with a reasonable mechanism for specifying the group id (I usually use the first few levels of the class package), artifact id (I used the library name) and version in the dependency. The hard part is that you have to manually handle transitive dependencies (aaa.jar depends on bbb.jar, but the app needs only aaa.jar to compile).