Can someone give me advice when it comes to moving up with weights?

I am using the "Fat to Firm: at any age" book to be my guide for getting in shape. The book advises me to start off small in my weights and go up in weight every month (or until I become comfortable with the weight that I am currently on). When a friend of mine started to accompany me to the gym he assumed the role of personal trainer and insisted that I go up in weight after every set. I became very frustrated because he would assign me a weight that I thought was a little too much for me and even though I was struggling with the weight after I completed a set he wanted me to add on 10 more lbs. When I told him about my book's guidelines for moving up in weight he told me my book was probably outdated and my method wouldn't be effective-- my book was copyrighted in 1998 and I don't if that is or isn't our of date. I want to know how to properly move up in weights.