Tip #1 Buy your shoes in the afternoon. Your feet will expand a little on a hot day.
Tip #2 Try different brands. Different brands have different cutting and width. If you wear size 44 in Shimano it may not be the same for another brand.
Tip #3 Make sure the crank bros cleats can fit the shoes that you are buying.
Tip #4 Some shoes use laces, some use velcro, some use ratchet. Choose according to your budget. High end shoes use carbon fiber sole, good for pedaling but this may not be comfortable for walking.
Tip #5 Shimano makes a wide range of MTB shoes, some look like road racing shoes, and some look like hiking shoes. The road-racing style have a narrower front while the hiking style have more room in front.(for those people with wider bone on the side of the foot)