Pick up a book about leadership, and you will find statistics about different styles. However, there is very little written about what works well.
One approach: Keep your door open. If you are to have good relations with those with whom you work (and for whom you work), you need to be accessible to them -- all of them.
Through the years, an open-door policy worked well for me -- in part. I announced the policy repeatedly to all constituencies, and I continuously tried to get people to "visit" when they needed my input.
Did the policy work? Not really. The door may always have been open, but far too few people walked through the doorway.
I therefore tried formal office hours both in my office and in the campus center. The more formal approach did not work much better. Ultimately, I concluded the important thing was simply being available. Whether anyone took advantage of the policy was less significant than having the policy in the first place.
Tangentially, when you do meet with someone alone in your office, always keep the door open -- literally. I was asked at times to shut the door -- I never did. Perhaps it was the lawyer in me who "cautioned me" to make sure no one could accuse me of anything inappropriate. With an open door, accusations are harder to make. Fortunately, I never had to defend myself or try to disprove a negative.
When individuals take advantage of your open-door policy, you should be respectful of them -- more respectful than I was. Young people today multi-task. While I really would not claim what I did was multi-tasking, I never broke myself of the bad habit of listening to what was being asked of me or told to me and, at the same time, working on another matter.
Open door? Absolutely. Respect for those walking through the doorway? Definitely.