I followed Dixondale farms instruction for growing onion. Here is the picture of my onion.

agmss,
I had the same problem last year with onions from sets, and followed advice to try plants. This years crop is looking much, much better. I have three beds devoted to onions, two of which seem to be having faster, more robust growth. Those beds had beans; one Fortex, one yellow bush (forgot variety) After I had harvested LOADS of beans I cut the vines, chopped them, and dug them back into the soil with relatively fresh horse manure. On one bed I planted a crop of field peas as a cover crop. Tilled in spring, no added fertilizer. Bed with pea cover crop seems to be doing best...

While I can't plant as straight a row as jamesandfely (nice crop guys!!!) I have harvested about ten pounds of reasonably sized Copra from a 20 foot row. Haven't harvested Patterson yet, but they look even better.

All of the above being said I am new to onions, and was advised against some of the things I have done. However gardening as an experience is all about balance. Keep notes and keep trying!