Tips for Perspective
It is not difficult to learn. You just need to go through the steps. You'll probably want to find some good illustrations to copy for practice. However, I want to give you some tips to get you started.
The first thing you want to do is figure out where the horizon line is. The horizon line is basically where the ground goes out of sight. However, it may be obscured by trees, mountains, or buildings. If you look at a seascape, the horizon line is easy to find. It is simply the end of the ocean. The problem arises when you have uneven ground that may be cluttered with objects. Don't worry about that. All you need to do most of the time is get the general idea of where it is.
On the horizon line, you will find a vanishing point. This is where things can get confusing. Vanishing points rely on where you are standing and which way you are facing. For example, stand in a hallway and look straight down the hall. This will give you one vanishing point which is one-point perspective. Now go stand outside. Face a building at an angle from the corner. Now you will have two vanishing points and therefore end up with two-point perspective. To get three vanishing points, stand on a tall building and look down or stand below a tall building and look up. If you are still facing at an angle, you will see three vanishing points and three-point perspective.
For one and two-point perspective, the vanishing points are on the horizon line. For three-point perspective, the third vanishing point will be way above or below the horizon line. You will rarely see this type of perspective though, so don't worry too much about it right now. Just keep it in mind.
Remember that all lines flow to these vanishing points except for a select few. For example, vertical lines will always be straight up and down unless you have three-point perspective. Horizontal lines will either go straight across, or they will go diagonally and point toward a vanishing point. You should really study some illustrations to learn more about this, however.
By now, you should have a better idea of how perspective works. All you need now is to do some practice. Soon, your drawings will look better and show more depth.