I can only agree with all the above, all great information.
I don't think you can nor need to surpress emotion, just make it irrelevant.
Personally the clincher for me was proof. Even after the years of backtests and then demo trading, I was still messing up constantly. I would take my profits earlier than my plan suggested and not cut my losses till the last second and hesitate taking trades or over leveraging.
As said before, trading is a business and after some serious weekend debate with myself and Mr Artois I settled on 2 options. Give it up or just do it. Correctly, properly and like the business it is.
Once I started my journal and traded the plan; to a tee, no questions asked, no second thoughts, no care nor attention paid to anything but the plan, it all came through. Another problem I always had was thinking too much! Despite all that happened and despite what the backtests showed I didn't have control before. As soon as I finished that month I had proof, in black and white and in my bank account that 1) I could do it, and more importantly 2) the plan I had devised, worked.
Since that point I have not had a problem. Nowadays to me, every trade now is akin to pulling a pint in a pub or answering the phone in a call centre because I know it works, and that proof was all I needed. I know the plan works in real time and backtests show my maximum drawdown expected so now I really don't care. Some lose, some win, sometimes I'll have a good run and sometimes a bad one but I know it always works out in the end. Now I just turn on, press the buttons when applicable and then turn off again, that simple. Only If I doubled my max consecutive loss run would I even slightly consider looking at my trading plan in more detail again.
I strongly agree with what timsk said; devise a plan, test the plan and then, IMHO all you need is to prove the plan. Once you can do all that, as long as its proven succesful, there is no need for emotion, you just get up and go to work and spend your days surfing the net in boredom like any other job.....
Just my 2 cents