Remove all noticeable fat. Fat causes the jerky to spoil much faster. Slice your meat into very thin strips less than 1/20" thick (sometimes a butcher will do this for you for an extra fee if you ask). To make it easier to slice, freeze it for about 5 hours before slicing. You can cut with or against the grain; some find that strips cut against the grain are easier to chew. Trim the fat as you go along, since fat does not dry.