Choosing bridesmaids may be extremely simple or extremely hard. I've always had several best friends at a time, and choosing a few who stand out without the others getting upset is a tricky task. Here are some things to consider when choosing...
Choose friends that you are close to and trust. Remember that they may be handling important tasks throughout the planning process and during the ceremony. You don't want someone who is often late, makes mistakes easily, or is forgetful.
You should be able to trust your bridesmaids to support you, your fiance, and your marriage. Don't choose anyone who might have a grudge against your future husband.
You don't need to invite every friend. There are a lot of positions in a wedding. Someone needs to man the guestbook, be a personal attendant, reader, man the gift table, etc.
Remember that once you ask, you can't take it back. Don't ask someone who you might wish you hadn't along the way. An invitation to a bridesmaid is permanent.
Make sure that they know all the expected expenses before they commit.
Don't feel like you have to ask someone to be a bridesmaid just because you were one of their bridesmaids.
Most weddings have between two and six bridesmaids. Another way to choose how many is to have one bridesmaid for every fifty guests.