The best thing about this is, crappie minnows that you catch come from the crappies' natural environment, in the exact water you will be fishing.  Bait shop minnows are sometimes caught at different bodies of water, and will be "foreign" to crappie which can cause crappie to reject them as a food source.  Plus, bait shop crappie minnows are usually more fragile-i.e. older, and dying from being in captivity.  Amazingly this is a little used crappie fishing secret , that few fisherman use these days.

STEP#1:  Walk around the lake looking for "shaded areas" close to shore.  The best place to catch crappie minnows is by boat ramps or boat docks.  Possibly because that is where fisherman dump their bait after they are done bringing their boats in.  But also because these areas offer good "cover" for minnows, along with food sources.

STEP#2:  You need to find areas that are between water depths of 4 to 8 feet.  You need these depths because of the limitations of your minnow catching casting net.

STEP#3:  Cast a 3-4 foot crappie minnow net with 1/4" netting holes.  This takes some practice.  The Idea is to cast the net "flat" so the largest area hits the water.

STEP#4:  If you can't find any good areas to cast your net or you're just not catching anything, then I suggest you try it at night.  You will need a good submersible fishing light to be successful at night, but your chances of success will be much greater.  The submerged fishing light will attract minnows like crazy!  You can either use your cast net, build yourself a minnow trap and drop it down near the submerged fishing light or use a bait store dip net. 

All these methods work great and you will catch your crappie fishing minnows in no time flat.