I wouldn't open a shop that sold only cigars. The best I've seen combine with another more lucrative business. Such as, a cigar shop/bar, cigar shop/gift shop, or cigar shop/tobacco store. The tobacco store and gift shop combos seem to suffer more than the others out of these combinations.

The most successful and best I've seen is a large cigar humidor and liquor store with a decent selection of basic booze and cigarettes, smoking/drinking accessories, fine wine, fine spirits, and microbrews along with the cigars. All the best liquor stores in town sell at least some fine cigars in a small humidor.

The lesson to be learned from the local business techniques seems to be, establish a fine liquor store, then build a walk-in humidor.