Whenever you get a set of letters with 'G' included, you can almost assure yourself that you can make a word.
Why is this you say? It's simple, you try and find a word which you can end with 'ing'. There are many highscoring words which end in 'ing', for example: Quizzing (36)
So now that the 'G' has been used to make 'ing', you have to use the other letters to form the main part of the word. 'G J Z' doesn't look good at first sight, one you use your 'G' to make 'ing', all that is required is to find a word with J and Z that the suffix 'ing' can be added to. Jazzing for instance.
This can be done with almost all combinations that come with 'G'. You should no longer see the letter 'G' as an enemy letter, in my books it can be among the most useful.