How do your prepare your #1 for another sibling?

we told him as soon as #2 is conceived. everyday we will tell him what it was like when he was still in my tummy. he was excited at every appt and I let him touch the tummy when there's movement. we also brought #1 to buy a toy for #2 and secretly buy another one for #1 for them to exchange during their first meet up at the hospital.