doing something wrong but can't figure it out

[Chino46]

I play limit hold'em at the .50/1.00 level and just cannot do better than 1/2 a BB per hour. I follow the advice of Small Stakes Hold'em by Ed Miller carefully. I'm on my fifth reading in as many months trying to figure out the problem but I just keep doing 1/2 a BB per hour, same as six months ago and I only play one table at a time so I'm not splitting my attention.

Any ideas? Is anyone doing better at .50/1.00 limit? Thanks in advance.