Practice is the key to success. Try to sketch almost anything and everything you come across.
Browse through various newspapers, magazines and online sites. Take ideas from various advertisements, posters, banners etc., you come across.
Keep your eraser away from you while practicing. It’ll help your lines become more bold and confident.
Give importance to detailing where ever required, like the face of a human figure or the human’s outfits etc.
Try to master the skills of human illustration. Concentrate more in proportions, form etc.
Calligraphy skills come handy in posters, banner design, etc. Learn and practice different styles of lettering as they can come handy.
Stick to the prescribed syllabus of the NIFT entrance exam.
While sketching first make a light sketch and later darken the drawing once you are confident about it. This helps you save time erasing mistakes.