Hii…one can surely prepare for campus placement . Infact 4–5 months nare sufficient to prepare well.All what is needed is to practice questions . Practice quantitative analysis, logical reasoning, verbal ability ,data interpretation.
Moreover keep in touch with newspapers and practice group discussions.
Also prepare your technical subjects , your favorite ones, say atleast 2 subjects.
Conclusion, practice well 2–4 months are sufficient for campus placement
All the best!!