Hi
Help needed,
plan to visit
Berlin
Prague
Amsterdam
Brussels
What is a good entry and exit point?
please also itinerary.....
thank you very much!

Check the prices for flying in and out of these cities. I am guessing Amsterdam and Brussels will have the best prices.

The inquiry is too simplistic.
Good entry and exit point for what purpose?
Besides airfare, the air itinerary matters. Some require stressful layovers while other might arrive at the destination at an undesirable time. It depends on when and where the OP is coming from. Neither is stated.
Not all the venues are open everyday. If the OP wants to do something specific with closure dates, staying in that city during the closed days would be a waste. Objectives of visiting each city are not stated.
If you visit a city when there is a huge convention going on would spike up the accommodation prices and decrease availability. Dates of travel matter. This is not stated.

Defining "good" might be helpful. I suspect if it is a matter of cost then the presence of low-cost airlines is going to be a factor. It is also a matter of where the OP is flying from and to. I agree that the inquiry is too simplistic given the lack of information.

I would be inclined to fly into Prague and out of Amsterdam, especially if coming from the US, but I agree that more info is needed. The OP should spend some time at skyscanner or itasoftware checking options.

How much time is this trip to entail?
Berlin
Prague
Amsterdam
Brussels

I'd fly into Prague
take train to Berlin and train or fly to Amsterdam
end in Brussels by train from Amsterdam
fly out of Brussels

Book train tickets yourselve online often at a discount- www.seat61.com has loads on doing that yourself online - general train info www.ricksteves.com and www.budgeturopetravel.com.

You could fly Prague to Brussels and yes then end in Amsterdam whose airport has a lot more direct flights to U.S. than Brussels. If time is short delete Brussels, a city that many here are underwhelmed with (it has its pluses but old-world ambience is not one of them) and spread time out between others - Amsterdam especially has some nice day trips and since Brussels is just about 2 hours by train it could be a daytrip from Amsterdam and save relocating hotels for one night and save about a half-day.

Nobody can say where you should fly into or where you should fly out of without knowing what your plans on the ground are, and it appears you don't have any except a list of cities. And you don't say how much time you have. Nor do you say what time of year. Nor who is traveling. Come on - give us some hints.

It's up to you to determine the itinerary.

no one can possibly give you advice without at least some of the questions StCirq poses.

Fill in the blanks and you will get useful feedback.

And, don't forget to plan on one day of travel between each stop - even if flying. And that landing day if all-night flight may have limited sightseeing value.