No matter how good a parent is, there are times when everyone needs help with it. There are no rules that apply to all situations and there are no manuals. Parents need to just do the best they can and keep on going.
Actually, there are loads of books available on parenting. And while the advice they offer is often beneficial, none of them have all the answers. They teach parenting skills from every possible angle, but none of the experts seems to realize that what works for one child won't necessarily work for other children. That is left up to the parent to determine, and it requires some type of categorization of the children. No matter how hard a parent tries, there are always going to be children in the brood that don't respond to the parenting style.
I always advise parents to read everything they can about parenting. There are books, websites and online chat groups to participate in. I've found that interacting online with other parents often provides solutions I hadn't thought of. The professionals can offer some valuable things, but those techniques and skills will always need to be adapted to different children and their personalities.
Don't be afraid to ask questions if you happen to have a tough parenting situation going on. Use the internet and ask other parents how they have handled the same situation. Sometimes the advice they provide is better than what the experts say, and the reason that's true is because the parents are dealing with these issues each and every day. Whether illness, school problems, or unruliness, parents have to wear a lot of hats, and they are usually happy to share their experiences and techniques.
Parenting struggles can really wear you down, but dont give up. Use all the resources out there to get the information and support you need. There are some really great information sites that offer you online resources and support at your fingertips. Dont be afraid to ask for help. All parents need help and resources to get through. You are not alone.