Language acquisition is not likely to come through a single method. Stories of learning English by "watching American television" are typically rather exaggerated. The same is true of the Pimsleur program. This is not to discount the value of this program, which contains some amazing sentence structure practice for anyone who wants to learn Chinese.
As a Peace Corps Volunteer in China, I have often wondered how to most efficiently learn Chinese and how to retain the information forever (the key here has been daily use of the newly learned language). Acquiring language is something that I am forced to think about daily as I confront a myriad of obstacles and challenges related to language.
So far I have created a list to meet my own needs as a learner, not all of which I thoroughly enjoy. This last point is particularly important because balance between fun and hard work is important (so one never gives up and still continually learns). If you speak English and you are studying Chinese in the United States, your list may be modified as needed.
Each day I commit to studying Chinese for 2 hours no matter what. I try to study mostly in the morning so that I do not give up on it later in the day. In addition to my studying I try to have several interactions each day using the language. These are generally friendly inquiries about directions to places I already know or prices of vegetables.
My study program includes Pimsleur; it is my "warm up" for working with a language tutor (I work with a tutor for 1 hour in addition to my study time). Actually, Pimsleur II contains a lot of the words, phrases and sentence structures I was introduced to during my initial intensive language training. I believe anyone who masters (80% or better) Pimsleur I and II can consider themselves at least an "Intermediate-Low" level speaker. Generally, I still use Pimsleur because it is excellent pronunciation practice. By mimicking the sounds I have been very successful in sounding more native-like (many people specifically praise my pronunciation rather than my Chinese ability).
I have begun an immense stack of flash cards, which serve to help me with words or phrases that are difficult. I use the `add-a-card' method, which is quite behavioral but it WORKS. These are all written in Pinyin, but I am moving toward a system of Hanzi. I use the series New Practical Chinese Reader, which has a workbook, textbook and teacher text. I listen to one lesson daily. I also read Chinese Grammar, which is published by Schaum's Outlines. I allot times each day so that I am studying for 2 hours. It's easier for me in China because every good conversation motivates me more, and every poor conversation does the same!