It takes me at least one week to submit a site in all that directories from vilesilencers list. On the first day I submit to directories with higher PR and than moving to directories with lower PR.
I've written some software which I'm testing at the moment which speeds the process up somewhat. It's still manual submissions but you can get 20 done in about 5 minutes!
I just sit down, put my headphones on, and go into a zombie like state for hours upon hours. This also happens when I am coding a new website haha.
The best way is to download Robo Form because it makes filling out the forms as easy as clicking a button (which fills out the forms for you). I can't even begin to tell you how many hours it has saved me.
It helps if you actually enjoy submitting to directories and have a supply of new music to listen to aswell, i can quite easily get into a zombie like state just like lschmidt mentions, until ive worked my way through a nice long list.
I agree, Roboform is a great time-saver for any kind of repeated form-filling tasks, especially directory submissions. Even the free version lets you set up 2 site profiles and the paid version is only about 30 bucks, last I checked.
The InFormEnter extension in Firefox helps me a lot too Although I still try to spread the time of submission into all the directories into several weeks or so.