Tools to increase freelance productivity

Since I'm thinking about how to relearn good productivity now that I'll be freelancing full-time -- at least for the time being, as I still haven't decided about the long term -- I've also been thinking about tools to help me increase my freelance productivity.  Freelancing is going to be more of a numbers game for me this time, since I can't depend on my husband's income to fill in the gaps in mine.  I'm going to have to be more productive so that I can be more self-sufficient.

Here are a few ideas I've come up with for tools I can use to help me increase my productivity.

1. Timer app: I have an app on my computer that I downloaded years ago.  I've used it for all sorts of things over the years, but I originally downloaded it as a productivity app.  I intend to start using it again to schedule breaks, limit social media time, and keep me focused throughout my day.  If I allow myself a certain amount of time for admin tasks, or blogging, or a client project, having a timer app snapped to the far side of my screen will help keep me on track.
2. Site blocker plug-in: I am well aware that Facebook is a hug time suck for me, less because of the social status updates and more because I'm addicted to educational news headlines.  Space, dinosaurs, child development, you name it -- I see the headline pop up and I'm hooked.  Unfortunately, this also means lots of time wasted on Facebook and reading articles referred to me via Facebook.  I'm planning to use a plug-in to limit how distracted I can let myself get, but I have to do some more research to decide which one I want to use, and whether I want to abandon Firefox and switch over to Chrome.
3. Timekeeping: I used to have a time sheet I filled out every day, with a list of tasks to do and my time spent doing everything, whether it was personal or work-related.  I filled out the to-do list part the night before, and kept track of my time on each task.  When I got my new computer a few years ago, I switched to a timekeeping app, but eventually abandoned it and stopped keeping consistent track of anything at all.  (Amusingly, I just opened the app and realized it's been counting my time every since as blogging work.  Oops.)  I don't know yet which method I'll use, as both have distinct and separate advantages, or if I'll decide against both and just use a simple spreadsheet, but in any case, I plan on going back to some sort of timekeeping system.

I'm sure there will be others, but these are the ones I can think of -- and am actively planning to use -- right now.  What about you?  Do you use any tools to help yourself improve your productivity?