So if you are learning caricature a good way to get started is by drawing iconic characters. Let your first caricature be Abraham Lincoln (see portfolio). Once you put on that beard, Presto! Then try something like Spock here. Easy Pickins! Of course it's a little harder when you do it live for regular folks but at least you'll feel good for a while. Speaking of caricature Here are a few live ones I did lately.
I really enjoy drawing people made in God's image. I just wish I was better at it. LoL