Lake Louise is a tiny town. There is not a great deal to see in the town, but the Lake itself is beautiful.
Even more beautiful is nearby Moraine Lake - definitely a must-see. There are many types of accommodation from the expensive Fairmont Chateau to budget backpacker places. There is not a lot of shopping available. Food and a limited range of souvenirs are available in the town. There are nice, often quite expensive shops, at the Fairmont. Many of these feature artwork and artifacts made by locals or by First Nation people. Lake Louise is a nice place to visit, but a stay of one or two days is plenty, unless you simply want to relax and do nothing in luxury for a few days.
Lake Louise is so beautiful. I recommend hike up to Lake Agnes Tea House and down. Then have high tea at Fairmont of Lake Louise oversee the Lake Louise.