Pregnancy
If you decide to use attachment parenting, this is the best time to do all the reading you can on the subject. You don't have to do everything you read, but adopt the things that will work for you in your own situation.
During pregnancy, it's important to focus on the positive aspects of becoming a parent. It's easy to become overwhelmed with thoughts of being a new parent, so I really recommend meditation, herbal tea (that is safe during pregnancy), and as much sleep as you can possibly get.
Preparing a birthing plan can help take some of the anxiety away about giving birth too. Even if things don't go according to plan (they didn't with me), having the plan really helps. Just don't get stuck on the plan. Be willing to adapt as necessary.
Infancy
Be prepared to have your newborn infant with you most of the time. Skin contact is so important, especially during early infancy. You can wear your infant in a front-facing harness or sling while you clean. Hold them as much as possible during the day, even while they sleep if it's not too hot and doesn't disrupt their sleep. If you can't hold them, keep them nearby and touch them as much as possible.
Give your infants daily massages. The best time for this is after a bath while you're rubbing in some baby lotion.
Breastfeed if it's possible. This helps to build very strong bonds with your newborns.
Never leave your baby to cry more than a minute or two. Sometimes it's not possible to get to them right away, but you should get to them as soon as possible. It's impossible to spoil a newborn baby. Crying is an infant's only way of communicating with you that there is something wrong, whether they are uncomfortable, in pain, hungry, or just feeling insecure. If you really pay attention, you can learn what the different cries mean. By attending to your babies as soon as possible you're assuring them that they can depend on you to be there when they need you.
Sleep with your infant in your room at night. I don't recommend co-sleeping because of the dangers of SIDS, but you can put their crib or a portable cot in your room. This is as much for them as it is for you. When they wake for nightly feedings, you don't have to go too far. Plus, you can respond to their cries in a more timely manner.
If you have to leave your infant (which isn't recommended, but sometimes necessary), it's best to leave them with another family member or close family friend who is supportive of your attachment parenting style.
Toddlerhood and Preschoolers
Children at this age are becoming more independent, but you should still hold them as much as possible, especially when they want to be held. Never turn away their desire for affection. If you can't hold them right away because you're cooking or doing something else that makes it difficult, ask them to give you a moment and promise a hug soon, but never make them wait more than a minute for each year of their age. So if they are two, don't make them wait for more than two minutes. You can even make it a quick hug with a promise of more as soon as you're done. Most of the time a quick hug is more than enough.
Tantrums are not bad behavior. They are a form of communication. Young children can't cope with extreme emotions like confusion, anger, and frustration. When they become overwhelmed with these emotions, they explode and tantrums are the result. So while you can't give in to a tantrum, there are ways to handle them positively.
Use the word "no" as little as possible. It's better to redirect a small child than to scold them. In fact, you shouldn't raise your voice to them unless they are in immediate danger. If they insist on touching things they shouldn't, they aren't misbehaving. They are curious. Breakable things should be put away until the child is older and can better understand why they shouldn't touch these things. You can use distraction methods too, especially if you rotate toys (only keeping a third of their toys out at any one time and rotating them each month so that it feels new to them again).
School Age
As they get older, they might not want as much attention, but always make yourself available when they do. It reinforces that you'll always be there when they need you.
Instead of punishments and "grounding", talk to your kids when they've done something wrong. Make sure they understand why it was wrong and come up with strategies together to prevent it from happening again. Helping a child understand how their behavior will affect them in the future goes a long way to helping them develop a sense of self-discipline and respect for rules and boundaries instead of seeing them as something they need to work around to get what they want.
Teen Years
By the time they are teenagers, they should have developed a strong bond with you. They are confident that you'll always be there for them and aren't afraid to come to you with their problems. Adolescence is a difficult time, so assure them everything they are experiencing is perfectly normal and that it doesn't last forever. Don't hesitate to get counseling if it becomes necessary (some teens really struggle during this time). Encourage them to explore their interests and help them discover how they can adapt their interests into a career. Even if they change their minds 100 times (which is perfectly normal), keep supporting and encouraging them so they can find their place in the world and live healthy, happy and productive lives as adults.