One of the best places to start your LSAT preparation is by taking LSAT sample questions and seeing how well you can answer them. This provides you with an understanding of the types of questions that will be asked and the formats they will come in but more importantly it will help you identify some areas of weaknesses and some areas of strengths.
This will allow you to hone in on specific areas to work on so you focus your preparation and achieve the optimal results. The Princeton review provides a full LSAT practice test which will provide you with not only LSAT sample questions but also a preview of the format, style, and give you an overall experience similar to that of actually taking the test.