When you are in career legacy mode you start out with a really bad team that you are going to have trouble winning with. I have found a way to bypass all of these troubles and make it easy to go undefeated, get ranked in the polls and win the national championship. This will get you some achievements and will allow you to be offered jobs from the schools in the power conferences. In the main menu of the career legacy mode go to options and then go to game sliders. Check the bottom of the screen to make sure that it is set to User settings/home settings. You will see a list of options about shooting, increase the first 5 options to 100. Then press 'RB' and this will take you to a list of attributes increase all of these to 100. There are two more menus after this labeled 'Gameplay' and 'Fitness', these two menus are up to you as they don't really effect anything. Now when you go to play a game all you have to do is shoot three point shots and just release the ball anywhere near the top of the jumper and the shot will go in, this will work every time and does not effect your achievements. After about 25 games, depending on your team you will earn a spot in the polls and get an achievement and you will win the national championship easily. In your second season put as many big name schools as you can get into your schedule and you will get ranked in the polls easier and more 5-star recruits will want to join your program. I have used this for one national championship already and I'm on my way to a second one with a team of players rated from 48-68 and I am playing against Duke, Marquette, Oregon, DePaul, and other big name programs.
I found this out while fooling around with some of my players appearances in legacy mode.
I was scrolling down the options that you can select to edit and there is a section that allows you to change the selected players stats.
So when you start a career legacy mode you can boost the stats of your crappy teams players so that they are all rated perfectly and you can win more of your games and get some achievements while doing so.
When you are in a game and are in need of creating a few turnovers call a timeout and go to "Press Settings".
This will usually be set at "3/4 court man" coverage and set for "Auto" or "Occasionally". Change this to "Full Court Man" and set it to "Always".
This will bring 3 of your men down to their end of the court and put pressure on the point guard and shooting guard who are the main receivers of the inbound.
Now take control of a fourth man and use him to intercept the passes on your opponents end of the court yourself.
Getting steals using this strategy involves great timing and a little luck. When you get the timing down you can gain those ever so important steals in the last minutes to either boost your lead or come back from behind and steal a win.