Here's a more complete answer:
1) Draw a line perpendicular to the curved surface of the mirror, through the center. This is called the principal axis. The point where it touches the mirror is called the vertex. Measure and mark the focal point. Measure and draw the object in position on top of the principal axis.
2) Assuming this is a concave mirror and your object is not in front of the focal point (the rules are still the same for a concave mirror and for the in-front-of-the-focal-point situation but it is a bit more complex), draw a line from the top of the object, parallel to the principal axis, to the mirror's surface.
3) The reflected ray will go from the point where it touched the mirror, through the focal point. Draw this.
4) The second ray is drawn from the top of the object through the focal point to touch the mirror.
5) The reflected ray for this is drawn from the mirror parallel to the principal axis.
6) The point where the two REFLECTED rays intersect is where the top of the image lies. The rest of the object falls to the principal axis. If the object is beyond the focal point, the image will be upside down. This is called a real image. It can be enlarged or reduce.
7) When the object is at the focal point, no image is formed.
8) When the object is in front of the focal point, a virtual or right side up enlarged image is formed.
To see these ray diagrams, go to: http://www.physicsclassroom.com/class/refln/u13l3d.cfm
you first have to go through the law of reflection and then the rules how to draw the diagram.
follow the rules in reflection.then it is easy for you.
Everybody is right.