You can start with Release Validation testing.
In Release Validation all you need to do is to check the nightly/TC/RC
against certain criteria. For example, let's take the latest nightly,
you can run test cases which are mentioned [1] and submit your results in the test matrix.
Note that each of the test cases[2] will have "How to test"
section which will have the steps (to be executed sequentially) and if
the results match with the expected results you can mark it as pass by
editing the wiki page {{result|PASS|<fas_username>}} . Always make
sure to check for "Associated release criterion" which can be found on
the top of test case page , if your test
case fails you can mark it fail by editing the wiki page
{{result|FAIL|<fas_username>}} and file a bug at RHBZ [3] under
Fedora.
You can always find the ‘current’ validation pages using these addresses:
You can also do update-testing, update testing is where a tester tests a package and gives out a +1 Karma for PASS and -1 Karma for FAIL. You can go to bodhi.fedoraproject.org where you can sort the packages with Fedora Releases and tags viz "pending" & "testing" . You can read much about update testing here [4]. You can also, use fedora-easy-karma for giving out feedback.