There are some basic tools of the trade that are intended for this.
Drafting Curves
Drafting curves are used for manually drawing flowing curves. Also known as French curves, they have varying shapes, sizes and cuttings made in the centers that are placed onto drawing materials and traced with a pencil or knife, making it easier to produce smooth curving lines. They are made from wood, metal or plastic and have metric gradation markings. Some models are flexible and can be bent into different shapes to provide almost endless possibilities for tracing curves.
Protractor
Another common tool used in drafting is the protractor. It usually is made from clear plastic and is a full or half circle with 0 to 180 degree or 0 to 360 degree markings on the outer edge of the arc or circle. These markings are used to measure angles by intersecting lines that can run clockwise and counterclockwise from the center or starting point, which is marked by a little hole.
Drafting Compass
A drafting compass is a tool used to draw arcs or circles. It is made from movable metal stems connected by a hinge that allows the width and angle to be adjusted. One stem has a spike or needle on the bottom and the other has a pencil or pen. Once the width of the circle that is to be drawn has been set, the needle end is set and anchored onto the drawing material at the center of the radius of the circle, while the end with the pencil is swung in a circular fashion to draw a perfect arch or circle.
Ruler
One of the most basic tools used for drafting is a ruler. Also known as a rule, it is a straight-edged tool made of plastic, wood or metal with measurement marking of millimeters, centimeters, inches. It can be up to a yard or meter long. It is used to measure distances and to draw straight lines from one point to another.