Mocks are an integral part of CAT preparation. Mocks are not just tests to check performance but they are useful to improve performance. Without giving mocks, it become almost impossible to dream for good IIMs. Buying test series from any good institute is fine, rest depends on your strategy to do well. A proper strategy to anaylse mocks is very important. So we have given some steps and tips to follow for analysing mocks.
After getting mock results just open the test and try to attempt each and every question by yourself then check answers simultaneously. Do not read the solutions without solving them. At least give some time to each question, if you are not able to do, you can check solutions.