I'm not Emily Post, but...

I've read a thing or two about wedding etiquette. Weddings are a long-standing sacred tradition and should be treated as such. This means there are certain rules that should be followed and things that should happen just because. I'll break some down for you here.

Invitations
--Don't send out invitations six months before your wedding. Most people would lose them and there's really no point in sending them out so early. Invitations should be mailed 6-8 weeks before the wedding date.
--Do invite significant others. If your friend is in a committed relationship, etiquette says you should invite your friend's partner. Those who are married, engaged, living together, or in a committed relationship of a year or more are considered a social unit and should not be broken up. Take this into consideration when doing the guest list.
--Don't leave people out. If you invite one cousin, you must invite all 20. If one friend is bringing her 4-year-old, everyone else must be allowed to bring their kids. People are very touchy when it comes to weddings, and the last thing you want to do is hurt anyone's feelings, intentionally or not.
--Do include reply cards with your invitations. This allows the guests to RSVP. The return date for the reply cards should be about 2-4 weeks before the wedding date. If people don't RSVP by that date, it is acceptable to call them.

Wedding events
--Don't plan your own parties. Most people give gifts at bridal showers and sometimes bachelorette parties. To plan your own make you look greedy. Leave the planning up to a member of the bridal party.
--That said, don't insist your bridesmaids throw you a party. A party is a gift and should not be expected. After all, the bridesmaids are usually the ones who pay to throw the party and to expect them to do so is greedy.
--Do only invite those who are invited to the actual wedding. You should never expect a gift from someone who isn't even invited to your wedding. If someone does give a gift, but isn't invited to the wedding, that doesn't mean they have to be added to the guest list. Send a thank you card and go on with your wedding as planned.
--Do send your party's hostess a nice gift or card to thank her for her planning. A lot of work goes into bridal showers and luncheons, and that work shouldn't be taken for granted.

Money
--Don't expect anyone to give you money for your wedding, not even your parents. If they offer, that's great. If not, sorry. Plan the wedding you and your fiance can afford.
--Don't put on any invitation that you would like money as a gift. This is incredibly rude and assumes that guests will comply. Some people are uncomfortable giving money as gifts.
--In some areas of the country, dollar dances are popular and nothing is thought of them. In other areas, dollar dances are looked down upon. You know where you live and you know whether dollar dances are acceptable or not. If most people in your area are uncomfortable with the dollar dance, don't force your guests to participate.
--Do thank those who give you money. Treat the money the same as any other wedding gift and send a thank you card to the person who gave it to you. It is OK to mention in the note what the money will be used for, such as the honeymoon or down payment on a house.