1. Encourage your adult child to be independent.  It is healthy for your child to support himself or herself financially, and it is probably best to begin training your child in this direction during late adolescence.

2. Avoid making their decisions.  Part of being an adult is learning to choose what is best for yourself, and it will be hard for your child to do this if you are the one making their decisions for them.  You can offer them advice but as a friend more than as a parent.  The final decision should be your child's.

3. Everyone makes mistakes as they grow older.  Allow your child to make mistakes.  This will encourage them to evaluate their decisions more closely in the future.  If you anticipate a mistake that could be very hazardous, you should warn them but do so without "pulling rank".

4. Avoid criticizing the things that you do not like because this will just create a chasm in your relationship.  You can express your disapproval mildly but do not become too extreme.  For example, "I do not really think that your boy/girlfriend is right for you but maybe I will see what you do when I get to know him/her better" is much better than "I can't believe you would disgrace our family with that $#!*& you're dating!". 

5. Learn the difference between a request and a command.  Many parents are used to commanding their children to do things; however, once they are an adult, a command may no longer be effective.  Requesting that your child do something for you is more likely to create an atmosphere that is condusive to building a friendship.

6. Support your child's independence.  When your child attempts to exert their independence, do not downgrade their efforts.  Build their confidence by praising their efforts.

7. Make sure your child is sure of your unconditional love.  They may be afraid to assert themselves or take risks if they feel they are in danger of losing your regard.  Be certain to express your love for them and let them know that nothing they do will take that love away.

8. Spend quality time together.  Treat your relationship with your child like a relationship with any other adult.  You need to invest time and energy into it to make it work.  This is especially true when the relationship is going through a transition.  Find something you both like to do and do it together.  Or go out to lunch once a week.  Set aside an hour or so once a week to spend together and stick to it.

9. Respect their rights as an adult.  Although it is easy to still treat your child as a teenager, you need to respect their decisions and opinions.  And the more respect you show them, the more they'll respect you.  It's actually very common for adult children to ask their parents' advice and opinions when they feel comfortable with them.  If you build a good relationship with your child, you won't have to "butt in" because your child will ask for your help.

10. Become friends with your child.  You want your child to see you as someone that they can talk to and trust so you need to talk to them and trust them.  If you confide in your adult child about your fight with your sister or the fact that you really want to take dance lessons, your child is more likely to feel comfortable confiding in you.  Relationships are give and take.