I like to look at other pieces if I’m having trouble drawing, especially when I’m drawing people. Remember, Google is your best friend. All you have to do is type in something like ‘watercolor tutorial’ or ‘how to draw realistic portraits’ and, bang, you’ll get over a million results.
Lots of people don’t enjoy using a pencil to make a realistic drawing because it’s boring. But making a realistic drawing is a great way to develop hand eye coordination. Other aspects could really benefit from these drawings. Patience is one of them. So pick up a pencil and start drawing something! You won’t be good at first but no one ever is, keep going! Anyone can do it with enough practice.