When you want to make some pcb with EagleCad,
there are many hard problems.
Schematic is like tangled net and Etching is complex and hard.
If you skilled at etching pcb board, it's still not easy.
But it can be real easy with prototype PCB and EagleCad
Step 1: Grid Setting and AutoRoute
First, you must change grid setting.
Check [Display] is on, and [Size] are 2.54 and 1.27
and move elements to grid exactly.
Set Autorouting grid to 2.54 and autoroute
Step 2: Print Board to Paper
print board twice.
First page is top and second page is bottom.
Disable Top Layer and check [Mirror], [Black], [Solid] when print second page.
Step 3: Stick Paper to PCB
Cut carefully and stick paper to PCB
Draw line follow mirrored paper with black marker on backside
If you have laser printer, OHP transparency film would be good too.
Step 4: Place and Solder It.
(this is my older project)
Place parts on pcb - even my 4 years niece can make it!
And solder wires through the line.