Protestants do not pray to Virgin Mary. I used to be Baptist. Also, they are into baptizing people, like Baptism.
Differences can be looked at from a variety of angles.
1. History....time of appearance of X denomination on the timeline.
2. Hierarchy....you have those that are very hierarchical all the way to those that have little (if any) apparent leadership (traditional Quaker.)
3. Sacrament ....those with supreme emphasis on specific religious rites all the way to those that appear to have loosely organized worship service.
4. Scripture ...those that have an critically central place for scripture and those that do not have scripture at the center of their worship. (I'm not including those as Christian that reject the authenticity of Scripture.)
5,6,7.... Other areas beyond time to relate.
WE CAtholics do not pray TO the Virgin Mary.
Catholics baptize too!