be encouraging!
Explanation:
Say nice things about the person whenever they do something good, or just in general what you enjoy about that person. If they ever help you, thank them for spending their extra time helping you. if they are going through a rough time, try and support them any way that you can, since that will show that you appreciate and care about the person. You can also go the extra mile and write them a nice note about something they did, or maybe something they are interested in (since that shows you pay attention when they are speaking to you). You could get them gifts as a token of your appreciation! there are so many ways you can appreciate someone!