Work on your experimental section of your thesis. No matter what stage you’ll have a rough idea of what instrumentation you’ll use, so you can start building this up.
Make some badass figures. Have a look at Adobe Illustrator or Inkscape (free to use) and make your figures beautiful. If you have the time, you might as well, and it’s something that often gets overlooked.
Similarly to point 1, have a go at writing your introduction. Background reading is really important for this and it’ll strengthen your overall understanding of your studies.
Learn. To. Code. I wish I’d done this ages ago. If you don’t have to manually fit all your data, your efficiency will go up when you do get back in the lab. There’s some great introductory guides out there for things like Python and MATLAB
Lab books been a bit thin and not well used up until this point? Make sure to write down all the methods you’ve been doing up until this point.
Create some test plans. What are you going to do stepwise as soon as you get back into the lab? Plan it out to be as efficient as possible when you get back.
Had a whole host of data that didn’t “work”. Consider writing this up as an emergency thesis chapter.
Write as much of a paper as possible. Got a figure or twos worth of data missing right now? No problem. Leave a space for now and write about what you expect you’ll see.
Remember, no one is truly efficient 9-5 every day. We have coffee breaks, lunch, chats with colleagues. Apparently we are only truly efficient for about ~3 hours a day, so make sure to cut yourself some slack. Think about using time management such as the Pomodoro method.
Arrange time to check in with colleagues every week. This is going to be an isolating time for many of us. I’ve seen some great online initiatives including #COVIDcafe for people to connect.