Not all of the answers here are very honest. Lets revisit this.
1. you cannot be a police offer.
If being apolice officer requires you to carry a firearm, you cannot do it.
2. you cannot buy girl scout cookies.
False. At one time this was discouraged. Joining the YMCA was once a reason for excommunication. Now those things are not really addressed.
3. you cannot be a cheerleader.
This is discouraged to be sure, but not forbidden. i am sure her and her parents would have to speak to the elders about it.
4. you cannot celebrate your own birthday.
True. Excommunicating offence.
5. you are discouraged from giving to charity.
You are neither encouraged nor discouraged, although most JW's do not. They give to the religion and go int he ministry work and consider it tantamount to giving to charity.
6. you cannot vote.
True. Excommuniating offence.
7. you cannot play chess.
False.
8. You are discouraged from buying a two door car-A "Theocratic" or "spiritually strong" Jehovah's Witness will have a full size car for the door to door work
False. Some may have this opinion (I knew someone who was removed as an MS in a hall because he bought a sports car), but officially this would be someone acting rouge.
9. Women cannot pray in the presence of men without a hat
True if the man is baptized.
10. Only officially approved sexual practices are allowed in marriage
True. No oral or anal sex. If other found out, you would get a talking to, and perhaps lose priviledges of service.
11. you must own your own wind chimes (for chasing away evil spirits)
False. I don't know where this is coming from.
12. You cannot join any clubs or sports teams
False. You can, although playing competative sports is discouraged and will keep you from having priviledges in the congregation most times.
13. you cannot wear any jade jewelery.
False......and weird.
14. Jehovah's Witness meeting places have no windows
False. many do, most don't. Mainly for insurance purposes and to avoid vandalism and distraction.
15. You cannot celebrate Mothers or Fathers day (it may produce pride)
Those holidays are forbiddedn. Excommunicating offence.
16. JWs are are fobidden to say "good luck"
Forbidden is a strong word. You wouldn't find one doing it, but if they did they would not be hauled off to the gallows. I would say this is false.
17. JWs in times of crisis, are strongly discouraged from consulting with family counselors, including mental health professionals who are not Jehovah's Witnesses
False.
18. You forbidden to say "God bless you" when someone sneezes.
See "good luck" for explanation.
19. You cannot participate in a school play
False.
Ok there you go.