Babies and children learn about the world by testing and exploring – it's their job to play.
We don't need to drill them with flashcards or quiz them on numbers and colors, and there is no singular activity or toy that builds brainpower. But there are some important points to keep in mind while your child is playing that will help her (and you) get the most out of the experience.
While your child is playing, it's helpful to think about your role as being your child's "assistant." Pay attention to what your child is interested in, and then follow that interest and help your kid explore and expand on it. Your toddler gravitates towards anything with wheels? Get down and race her with another toy car or build an auto repair shop out of blocks. Your baby gets a kick out of her newfound ability to clap? Sit on the floor facing her and sing songs that utilize hand movements. We have a natural inclination to teach our children, but the best learning happens when we're helping them following their own interests.
Take a Back Seat
While your child is playing, see if you can resist the urge to over-help. If she's just learning how to use a shape sorter, the trial and error is part of the game. A certain level of frustration is healthy for kids, because it motivates them to problem solve. See if you can take a back seat during play and just narrate or offer suggestions: "Hmm, it looks like this piece is too big to fit through here," or "I wonder what would happen if you put the block in the middle…would it still fall over?" Giving our kids the answers doesn't help them as much as encouraging them to think and strategize on their own.
Unstructured and Imaginary play
Most kids gravitate towards imaginary worlds, and psychologists think it is a vital practice ground, not just for creativity, but for social and cognitive development. Imaginary play has been linked to "executive function," which includes our ability to focus, plan, and solve problems.
So it's important to protect time for unstructured play—it's just as important as the music lessons and sports practices. It allows your child to get inside her head and create an imaginary world; this is the way kids work through different possibilities and scenarios, take on roles and practice sticking to rules that they themselves create.
More is Not Necessarily Better
Finally, most of us acquire toys from birthdays, hand-me-downs, and holidays, and the result can look like a toy store explosion in our homes. As much as possible, keep the play areas ordered (this might mean rotating or putting away objects) so that your child knows where find things and he is able to purposefully take something out and play with it, without being distracted by other activities or materials.