May I suggest the best pre-trip purchase is an Eyewitness Guide to Prague? The book has great pull-outs of major attractions. Many areas of Prague are best viewed on foot--cars/buses aren't practical in some neighborhoods--nor are they permitted in some. The Prague card for transport is a no-brainer for a 3 days or more. You may not use it the first day unless you're adventurous to get from the airport to your hotel. There are great apts to rent there--our first was a few blocks fromCharles Brdige and the second was even closer in the embassy area--less than 100 us--one slept 5 the opther slept 3+ I will be happy to recommend the places we stayed. They like airline people and if you mention it--they may be happier and give you a better $.
We found the castle area nr charles bridge most fun for sightseeing--there are tour office right by the bridge. Petrin Hill and the funicular there is too cool--then you can walk down after seeing the view from the tower and eating some sausages. There is restaurant halfway up the funicular called Nebozizek--a bit pricey for Prague but a view to die for--grab a glass of vino or easy lunch--or an extravagant dinner. They have gorgeous rooms/suites but nearly always sold out--only 4.
We loved thechanging of the guard at the palace, but if you ask how to get there--up the main hill street you can start with them leaving the barracks.
I'll add more later--when I ck my records--and you get more here.