My greatest advice would be

1) Keep an error log to understand your weaknesses. After you identify a pattern in the log of questions you get consistently incorrect, work problems like those. For instance, I am really bad at rate problems - a fact I learned from my error log. After I determined that rate problems were killing my score, I reviewed the funamentals and worked rate problems until my fingers bled.

2) Review explanations to the questions you got incorrect. For that matter, review explanations for the ones you got correct as well. Reviewing answers you got incorrect will teach you where you went wrong. The next time you get a question similar, you will remember your mistake on the first.

Hope this helps you. I learned these tips the hard way!

pls tell me, what other materials to concentrate on further?