A child under 12 months doesn't require an educational toy that's overly complex - the main ingredient will be your interaction. The best way to decide upon the right type is to choose age specific toys, as something meant for a two year old is beyond the understanding of a younger baby.
Happily, there's a great selection of quality toys available that will help you to interact with your little one from a very young age. All of them embrace the use of vibrant colors, some use sound and other use both.
Vision and hearing are both great ways of engaging a young baby's interest and once they're old enough to hold things they will help improve their motor skills and co-ordination.