My advice is to check out a handful of parenting/discipline books from your library.
There are a ton of methods, and trains of thought on parenting, even on this board. And each parent is different. I could make a ton of suggestions and tell you what I do, and it probably won't be quite right for your family.
Get a few books, browse through. Return the crap. Then read in detail things that you think would work, then try implementing it for a few days/weeks, however long you're comfortable to try it.
FWIW, my favorite parenting book was written by Jo Frost, the Super Nanny lady. I found it to be a very positive book, and yet realistic.