I would like to know, if I meditate on the form of my guru, what process will take place? What will happen in my dhyana (meditation)?
—Vivek Sharma, India
The rule is this: whatever you meditate on, or concentrate on, you will absorb. For example, whenever you concentrate on something dark, your mind will absorb that darkness. If you concentrate on something luminous, your mind will absorb light.
So if you meditate on your guru, you will absorb his vibrations, his consciousness, his inner state. The stronger your concentration, the stronger the effect will be.
It is especially helpful to meditate on the eyes of a Guru: you will receive his spiritual magnetism.
If you meditate on the formless, divine, eternal consciousness of a true guru, a sat-guru, you will open your soul-door to that blessed state.
You can meditate also feeling the Guru within your body, or sitting next to you, or in front of you, looking at you. Swami Kriyananda sometimes meditated visualising his Guru in miniature form sitting on top of his head. So there are many possibilities.
In short: we cannot precisely say what happens to your meditations if you meditate on your Guru. But one thing is certain: it is a very beneficial, helpful and uplifting practice.
May your Guru bless you,