How you reward your baby will depend entirely on what makes your baby tick. Thankfully, many babies are the same and have similar needs. At the start, I would suggest just getting really excited when your baby makes a sign or seems to really be trying. A 10-month-old-baby will be delighted to see you cheer them on with an excited voice when they make their signs. You can also clap your hands, jump up and down and carry on in any other way that suites your personality.
When your baby makes a sign for the first time, strongly consider offering them what they have signed. For example, if your baby signs CRACKER, offer them one immediately, even if dinner is just around the corner. You want to encourage your baby to sign and if you wait, the association will be lost. While it might spoil dinner just this one time, the sign, because it is rewarded, will become solidly reinforced making it permanent in your baby’s vocabulary. So the general rule is to always reward first signs. After your baby has signed the word a few times, it’s not necessary to reward it. Doing so might even spoil your baby – but this is another discussion altogether!
So for now, just assume that you can follow through on first signs, and always reward attempts or successes with clapping and overall excitement. If you fall into the trap of offering tangible rewards like food for any and all signs, at one point your baby will come to expect it and be upset when they don’t get it or will not sign unless something is offered. Communication is innate to all people, babies included, so the progression is for signs to just happen. In other words, babies will eventually just sign for the sake of signing – talking for talking’s sake!