If you are starting from the scratch and if you think you are weak in English then start with wren and Martin book and then slowly switch to word power and other materials from the coaching institutes.

For maths also, if you think you need a recap then start with NCERT and slowly go for materials and all.

Same with LR/DI. First solve some basic circular, seating arrangements problem and the up your level.

Your aim must be top IIM'S or XLRI Jamshedpur. FMS Delhi is quite good too.