Hi everyone

i am just about to graduate college and planning a trip from the US to europe with two of my friends for one month!
We have a list of cities in mind and after looking at the map and some flights here is the idea of where we are planning on going.. not exactly sure on how to get from each place or how many days we should spend in each city just yet.
Are these countries and the flow cohesive? Any advice/changes/recommendations would be greatly appreciated. We know that we are trying to see a lot of cities in a short period, so any advice on which cities to cut off and try again another time would also be helpful! thanks so much in advance!
fly into London>paris>amsterdam>Berlin>Prague>venice>Barcel ona> fly home