Fist of all, this is a very open ended question. To make the most out of this platform, you should ask specific questions / problems you might have.
Coming to the problem you mentioned, the first thing you should do it put a framework around the problem and collect data according to that framework. For example, you will need to define the time period over which you are trying to predict the attirtion. Is it 3 months / 6 months or even longer.
Once you have done so, you can start putting business hypothesis around the problem and build the features / variables accordingly. In terms of modeling, the simplest would be to build a logistic regression around the problem. You can even try other classification techniques like SVM. If these do not provide good enough results, you can give survival analysis a try as well.
Hope this helps.