I would suggest keeping it as a constant focus in your mind and feeling the way there, but it would probably matter on what kind of dead you wanted to meet via Astral Projection. You could enlist the help of spirits and even reapers, and do petitions that call on forces to help you through the way.
You could meditate while thinking of the person you want to contact before trying AP. Having an object belonging to that person would be useful too.
However, the dead should not be disturbed unless utterly necessary nor for long periods of time as they have a process to go through in the afterlife and bringing them back to our plane of existence could have negative consequences for them.