What are their results?
Are you taking advice on getting a baby to sleep through the night from your friend with one young child? How do you know their child doesn't just have a different personality than your child's? Are you taking advice on how to not "spoil" your baby from Aunt Jessie who has a terrible relationship with her grown children? Are you listening to breastfeeding advice from a woman who lost her supply at four months? It's OK to look at how credible the source is before you allow any of their advice to seep in. This is not to condemn them, because no one is perfect. However, seek out those who are very knowledgeable about what they're saying. And remember, memories from older generations about how easy it was probably aren't very accurate if they haven't had young children in many years. This is also something to take into consideration when reading articles from people you don't know. You have no idea what their children and family are like.
What works for your family?
If I could give one piece of advice to new parents it would be to stop reading parenting magazines and websites if they find themselves second-guessing everything they're doing. They tend to be written in a one-size-fits-all, very mainstream attitude. What works for one baby or one family won't work for another. Trust your instincts and do what makes life easier. I think one reason family size has gone down so drastically is that parents are so bombarded with the "right way" that just doesn't work. It makes parenting less enjoyable when you always feel guilty about how your family has worked things out. One of the most important things I do as a doula is to give parents permission to do things the way they want. You can put your two-year-old to bed in their clothes for the next day. You can feed your newborn even though she nursed 30 minutes ago and is still crying. You can have you 10-year-old make their own lunch for school. A line that works to silence most unsolicited advice-givers is, "This is working for us right now."
During the first postpartum months you may find yourself especially sensitive to negative attitudes about your parenting. Sometimes it just takes a reminder that you will ask if you want advice, but with especially pushy people it may be best to just have some breathing room while you and your family adjust. Most people who bring up concerns are honestly looking out for what they think is best for you and your baby, but bringing up the subject over and over or in a rude way is never called for. When there are people in your life who criticize and cause doubt it is best to distance yourself from them.