Attempting To Dreamwalk. Tips Or Advice?

I have submitted a story here already outlying the majority of my abilities and experiences, but as I have read around I became interested in the concept of entering the dreams of others and becoming lucid in my own dreams. I'll start of by mentioning I have been lucid in my dreams before, but it only occurs about 5% of the time where I have dreams that I can remember. I have also "shared" a dream with someone before, where we both remembered details that were exactly the same in each of our dreams, which we had on the same night. With that in mind, perhaps I have done it once before without knowing how to? Or did they enter my dreams? I'd like to mention it was the first, and so far the last, time that person has ever been in a dream of mine.

Now, my first attempts at entering another's dreams were uneventful, but still interesting. I went by instinct and logic, first trying to make a mental connection to the "target" and a sudden realization hit me. I seemed to be convinced, that if it did work the way I wanted it, one of two things could happen. If they were asleep, I would enter the dream, and be returned to my own body when they awoke. Or, if they were still awake, and this one somewhat troubled me, I could end up stuck until I figured out how to send myself back. Does anyone know if there is any validity to these thoughts that my mind seemed to take as fact? When I explained these thoughts to the person I had intended to visit, they then forbade me from trying it on them again from fear that I would slip into a coma.

So I ask again if these strange thoughts of mine hold any weight, and if anyone has any advice for helping me to grasp this ability further?