I am going to Poland and will be meeting and staying with my friends parents. Would really like some advice on customs, traditions...how should I greet them, should I offer to help with cooking, nice gifts etc. The only posts I could find relating to this are for men meeting their girlfriends parents, are the customs the same for women?
I would be really thankful for any help, as I would really like to make a good impression.
Well, Poles don't bite, so you don't have to apply some special measures during your visit. Behave politely, but without exaggeration.
Some people don't like others to meddle in their cooking, so maybe just offer to wash the dishes :) but only if your friend does, because the parents may 1/ approve your politeness, but 2/ may also feel uncomfortable with a guest working in their house (generally guests don't do anything, they just have to enjoy the dinner and eventually drinks, but if you'll be staying for a longer period, then they probably can't "wait your table" all the time, I really don't know, it depends on a family, so you may offer your help, but rather not on the first day).
Dzień dobry. Miło mi Pana [or: Panią or: Państwa] poznać.
(means: Good morning/afternoon/day/how are you/hello. Pleased to meet you.)
[you use "Pana" - to an adult male; "Panią" - to an adult female; "Państwa" - to a mixed group, i.e. mother and father]
Cześć = Hi (to a younger person, if your friend has any teenage siblings/relatives).
(Pronounciation: usuful ink to a Text-to-Speech online software, you can also learn how to pronounce the parents' names correctly, but you need the right spelling, this software doesn't correct your mistakes, just tries to read as it's written, so using the spelling without Polish fonts, for example Wladyslaw instead of Władysław, won't do any good).
Gifts - I don't know. Do as you would do with your friend's parents anywhere, it's really hard to generalize.