The JW beliefs and religion are quite fragile and brittle, so the rules you ask about are generally there to seperate JW's from 'the world' physically and mentally. Independence and free choice are the enemies of the JW religion and the defences against such evils are quite strong - but it's not that compliance is forced in the sense of physically stopping people from doing what they want to do, so much as the rules are deeply embedded in the social structure and are often strictly enforced with formal sanctions.
1) what is meant by saying not dressed like a JW.. is there a specific code?
Out of meetings it's conservative dress, always neat and tidy... and modest... Anyone who dresses outside of the accepted style/code is treated with suspicion. Revealing or tight clothing is associated with immodesty and unchasteness; highly fashionable clothing is associated with immodesty, rebelion or 'making a showy display' of self, the list goes on, but modesty, conformity and blending in are the basic rules. Modesty, modesty, modesty... it's always modesty....
The code for meetings is conservitive business dress - suits, ties, long skirts, that sort of thing, but always modest...
2) are only men allowed to rise in position in the Hall?
Yes. The only 'position' open to women is to be a 'Pioneer'. That's a full time volenteer evangeliser, it used to be 90 hours a month and mostly they support themselves with part time work. Oddly, it's quite a popular thing to do. It's quite a prestigious position and allows a certain 'holier than thou' status.
3) Are young marriages encouraged?
No, but they are common. That's probably because of the strictly enforced ban on premarital sex.
4) are you allowed to associate (as friends or date) non JW's?
Friends - not really, but it's strongly discouraged more than banned. The way JW's are trained to think also makes it hard to form and maintain relationships with people who don't think the same way. Someone who's spending a lot of time with non-JW's would be treated with suspicion.
Dating non-JW's is a no-no and will provoke a lot of 'counsel' from the elders, but it's more the effect on the JW's adherence to the religion that's at issue than the dating. If someone was determined to marry a non-JW and did so, I don't think they'd always be removed from the JW's (unless they spent too much time alone in a house before the wedding, then they'd be presumed to have had sex and would probably to disfellowshipped), but they would be very marginalised socially and religiously... It's basicly banned and is quite rare. When it happens, it's usually women who do so.
5) are kids discouraged from after school activities and if so why?
Strongly discouraged and socially unacceptable. It distracts them from JW activity and molds their way of thinking in ways that are contrary to the way that JW's need to think to stay JW's and dedicate their lives to JW's. Dedication to the football team is taking away from dedication to religious life.
6) are the woman discouraged from working? Most I have met are not employed. just a note that I've noticed that the ones I have met are great with make up and hair (just an observation)
No, many work. They do tend toward traditional family structures and it's fairly common for women to stay at home, but it's not a religious matter whether women work or don't work. Religious issues would only arise if the nature of the work or time spent there had an adverse effect on their 'spirituality' (like reducing meeting attendance). That's the same for men but in the case of a wife there is a religious issue: either the husband is failing to provide, or they're being materialistic. Then we get into the 'headship arrangements', and that's quite complex...
Hair and make-up? It's a very competitive business being the best looking woman at the meeting and to do so within the modesty rules! I'm told it's the main sport amongst the women to scrutinise in minute detail what the others are wearing and how they're made up and all that... perfection is the only acceptable standard.
7) can anyone attend a convention
Yes, they're very keen to have as many there as possible (although security is said to be more of an issue now than it used to be, so that may be changing). The public can attend all their events.