Measure twice, cut once. -An English proverb
You will never regret having a good variety of measuring tools handy. Here are the ones I use regularly:
- 18" metal ruler - Having a metal ruler is useful when you need to use a knife, or even a heated tool like a foam cutter, alongside it. It takes a lot of effort to nick the edge of a ruler like this! I also find it helpful to have a ruler that measures in both imperial (inches) and metric (centimeters and millimeters). Sometimes the precision of measuring in millimeters is invaluable! You can find metal rulers at office and school supply stores, though you may need to visit a craft store to find longer rulers.
- 12" plastic ruler - A thin, bendable plastic ruler has the advantage that it can go around curved surfaces. I also cut one end off of this ruler so that the edge exactly lined up with the zero inch mark. These rulers should be available at office supply stores, just make sure you don't get one of the rigid plastic ones. I received this one as a giveaway.
- T-square - This is a lovely technical drawing device I picked up in college. It's a 30" long metal ruler with a t-shaped lip at one end. As long as you line up a paper with the edge of a table, you can use this to draw perfect vertical lines and to measure out horizontal lines at precise 90° angles as well. These can be bought from craft stores or anywhere drafting supplies are sold.
- Compass - A compass is the perfect tool when you find yourself in need of a drawing a circle. They are inexpensive, but make drawing a precise circle very easy. Like the protractor, you should be able to find simple compasses like these among office and school supplies. Larger and more sophisticated ones are available as drafting tools.
- Protractor - These are used to measure angles, which comes in very handy now and then! They can be found pretty much anywhere office or school supplies are sold.
- Measuring tape - This is a flexible seamstress' measuring tape, very useful for measuring around objects (or body parts, for costuming). They can be purchased from craft and fabric stores.
- Retractable tape measure - These tape measures are usually made of metal, curved in such a way that they stay fairly flat once extended. They come in different lengths, anywhere from tiny 3' ones for keychains on up to over 100'. They are available from tool and home improvement stores.