You already know the E form of the harmonic minor scale. Here are the other four forms.
Once you are comfortable with the fingerings for these forms, try using them to create some licks. Here is one derived from the C form in C minor. This one has a Classical flavor to it. Many metal players, (e.g., Yngwie Malmsteen and both guitarists from Metallica) are influenced by Classical composers, particularly Bach and Paginini.
This solo uses all three types of minor scales. Take it slowly at first and be sure to get all the techniques such as vibrato, bends, slides, slurring, etc. In bar 12 you will see three lines under each of the quarter notes. This indicates a technique called pick tremolo which means repeatedly picking a note as fast as possible. Practice it on one note until you have control of it.