How long are you going for? - it's one of my favourite cities, we keep going back as we've some very good friends living there.
Another tip I forgot (it's probably at the end of one of the links in the thread above) and something that catches a lot of visitors out.. when you get a public transport ticket you must validate it before use, this includes the weekend/weekly passes which need to be validated before their
first use (the period their valid starts from the day they are stamped - stamp a 3-day ticket at 11pm on Friday and it's valid to midnight Sunday, Friday counts as the first day). If you're caught without a validated ticket there's a fine. Having an unvalidated ticket in your possession is no defence.
Grab a copy of Tip (
www.tip-berlin.de) when you get to the city to find out whats on, looks like there's a William Klein exhibition at C/O Berlin (
www.co-berlin.org/en/william-klein) starting at the end of April.. and if you're in the area the quirky Museum Der Dinge (Museum of Things) is worth a short visit (
www.museumderdinge.de).