There are three things to know about metal working: i) metal is hard, ii) metal is heavy and iii) metal is sharp. Using these astonishingly obvious properties to one’s advantage is what separates the novice from the expert metalworker. Other than the very few who smelt or smith their own metals, most metal projects require the purchase of materials in preformed shapes (whether ferrous or nonferrous metals) that need to be cut or bent into the desired shape.
Metal is Hard - Marking metal is not as easy as marking wood or paper, and often the associated cutting techniques will make reading a mark or following a line difficult. For thin ferrous metal (such as sheet metal), a fine-tipped permanent marker is advised. Use a grease pencil, permanent marker or, if using a torch, a scratch awl to mark thicker steel. For all nonferrous (copper, brass, bronze), a scratch awl or fine-tipped permanent marker will be sufficient. To make cutting and shaping large pieces easier, it may be worthwhile to anneal (soften) the metal. Ferrous metals are softened by heating to a bright cherry red and leaving buried in a nonflammable insulator (such as sand or soil) until cool. Nonferrous metals are softened by heating to cherry red and cooling as quickly as possible, such as submerging in a large quantity of water (known as quenching). Both techniques can be reversed, though with unreliable results, by reheating then quenching ferrous, or by slowly cooling nonferrous. Both techniques will damage any existing finish on the piece and accelerate corrosion. Although any blade rated to cut metal will cut any size or type of metal, it is better to use one suited to your project. For sheet metal up to 1/6 inch thick, be it ferrous or nonferrous, common scissors may work, though metal shears may be optimal. Thicker metals will necessitate the use of fine-toothed saws, such as a hacksaw or band saw. Grinders can be used on heavy-gauge steel, but because of their relative softness, are ineffective on nonferrous metals. Drilling metal improperly is a good way to ruin tools and frustrate and possibly even hurt yourself. Always use a center punch to mark exactly where you want the hole, set the drill bit tip gently into the dimple and start drilling. The larger the drill bit is, the slower it needs to spin. When drilling ferrous metal, use sufficient cutting oil to keep the drill bit from getting too warm. With nonferrous, oil is needed only on pieces 1/4 inch or thicker. When your drill is about to penetrate the piece, lessen the pressure, slow the drill and be ready for the metal to "grab" the bit and jerk the drill. This happens every time and can be extremely hazardous if the operator is unprepared.
Metal is Heavy - The common advice of "always support your work" is of special importance when working with metal. Aside from the obvious safety concern of a falling chunk of metal, unsupported metal will bend under its own weight, and fixing such a bend is very difficult. Also, letting a piece flex while cutting will create an uneven cut line.
Metal is Sharp - Cleanup after a project is always important, but doing so after metal work can be hazardous. Unlike sawdust or plastic shaving, metal shavings are extremely sharp and can be very fine. Lay an inflammable container directly under your cutting area to collect the shavings as they fall. When new, blanks of metal have their edges softened to make for easier and safer handling. After cutting, all new edges will be extremely sharp. Use sandpaper, a file, grinder or wire wheel to smooth rough edges.