Tanking is the cowardly way out of a tough (no pun intended) situation. It involves losing games on purpose to get a better draft pick, also you reduce the total salary of your team to bring in the most revenue. Two things are wrong with this strategy. First and formost you are not guarenteed to get a stud draft pick, and if you don't you have just mortgaged your entire season for nothing. Second once you have wasted one whole season of losing, you then have to then spend at least one more entire season in a lower division trying to get back to where you started. If you read the news report that came out in the middle of the playoffs last season it states that they are trying to discourage this by making it less rewarding.
In my opinion don't take the cowardly way out. I have made it to Div III. by training players and selling them a season or so after buying them and mixing in some good veterans. Also you can survive in division IV by simply managing gameshape and enthusiam. The games you know you can't win take it easy, and then the games that might be close you can normal them and since your enthusiam is higher than their's (most likely) you will more likely win those games. And don't become predicatable in your tactics so others will have to guess what they should play against you. And on the other side, do some research on your opponents to see what their tendencies are.