For many years, when we were forced to leave our comfortable home to buy strings, we trusted our favorite salesman to recommend us an adequate set. Thanks to the Internet, there is no need to waste such energy now... But it is easy to get lost with all the options available. Here are some tips to avoid choosing strings based solely on the packaging.
Two things I would add. First, if you like guitar tones withoout a lot of twang, try pure nickel strings. The overtones in pure nickel are more in tune than in nickel plated, so the sound won't be quite as grating as it might be with nickel-plated. Second, There are boutique brands of strings that cost more but have amazing differences from the "usual" brands. For example there are Curt Mangan Strings. He used to work for Ernie Ball then went out and opened his own string factory. The consistency of his strings from set to set is unmatched. Thomastik-Infeld are rather expensive compared to the usual brands but they have a sound that is in many players' opinions head and shoulders above the usual strings.