How do I get my baby to try new things?

i take care my cousins 3 month old. he only likes his bouncer seat, but like you said, it only lasts for so long. he isn't at the stage where he likes rattles and i bought him one of those mats for christmas so i'm hoping that entertains him a bit! i don't want him to get into the habit of being held all the time. we do a lot of interactive things. i'll lay him on the floor or the couch and we'll play. we'll do "this little piggy", "itsy, bitsy spider" and other things like that. we "exercise" and do stretches. other than that, there's not a whole lot i can think of you can really do with a 3 month old. as he gets older, it does get easier. he'll learn to entertain himself.