Well, I'd encourage only doing this with ancestral spirits not every deceased person.
Incubation was actually a popular practice done in necromantic oracles. An "at home" version could simple be a prayer and offering to the particular spirit. Ask them a question or to come and visit you in your dreams.
You could change it up a bit. Add a candle, satchel, or some other charm to help the process. With the candle, you could get a bowl of water and a tea light. Take the tea light and put it into the water (there only needs to be a little bit of water in the bowl.) Set this somewhere safe, a stable place you won't knock it over at. Put a pinch of sugar in the water. Say the prayer, call the deceased person, ask for a dream, and then light the candle.
You could also do a meditation or affirmation before sleep. Word it in a way to call on the person and invite them into your dreams.
Wish you luck!