SNAP preparation is not very different from CAT preparation in terms of concept building. The area where it differs it, the level of questions, the time allotted and the online vs offline pattern.
For SNAP, once are done with the concepts,start with mocks. make sure you are able to judge the questions properly, so that you do not go about attempting every question and wasting time. Decide on which section to attempt first also.
The exam also has a GK section. The questions are generally not not difficult but to answer it correctly make sure that you are aware of all current affairs. Read newspapers regularly and maintain a document which will help in easy revision.
CATKing has great material for SNAP preparation. The GK questions in mocks really helped me in attempting that section in the main exam.