I recently worked for Wal-Mart, and we arranged alphabetically. Even though I'm familiar with brand names and their corresponding generics, I liked that method. Hopefully techs will learn brand/generics when they're typing labels.
When I worked at a hospital, it was so confusing. Everything was arranged alphabetically by generic name, even stuff that was brand name only. Not to mention the fact that there was a "hot section" with supposedly commonly used drugs, which would have been great if not for the fact that the drugs in the "hot section" must have been chosen 15 years ago because I never used any of them. Oh, and by the way, some little vials were mixed in with the tablets and capsules, but some were the counter, and some were on a shelf on the other side of the pharmacy. There were some syrups on the counter, some underneath the counter, and some hiding on a shelf in the back. Then there was the "eye section," the "ear section," the "OB section," and the "derm section." On top of all that, there were three huge refrigerators, but they were not arranged in any type of logical fashion, so you just had to memorize where everything was.