Take the time to get down to where your baby spends most of their time. If your baby is crawling, get down there with him and really have a look around from his perspective. You might be really surprised by how big things look as they tower over you. Hopefully, this experience will teach you about how a baby sees the world and how important it is to get down to your baby’s level to sign.
Peering up at adults all the time is intimidating and can come across as a power play. There are a few ways to minimize height differences between you and your baby. Obviously the easiest is to just kneel or crouch/squat down. Conversely, you might consider bringing your baby up to your level. This can be done at feeding times through high chairs or by putting your baby on the couch and sitting next to them. Moving baby onto your lap is also a great way to show them signs which can be done with your arms wrapped around your baby. Any way you can get close to your baby and create intimacy will assist you in connecting with him. If you can manage to get face to face on a level then you’re going to garner the maximum attention and efficacy from your baby.
As a final note, gaining level with your baby will ensure that your baby is able to see exactly what your hands are doing. There might be times when a table edge or other obstruction might block your hands from view. While you might make every attempt at signing, they won’t result in learning if your baby can’t see what you’re doing.