Paying extra attention while browsing the web is definitely the best method to avoid getting your PC infected with various types of threats, including ransomware.
Nonetheless, there are some additional measures you can take, such as using LockMyFiles to ensure your private documents are not accessible by any unauthorized users, including hackers.
This application does not even need to be installed onto your PC before you can access its highly user-friendly main window. All you need to do is to select the files you want to lock using two methods: via drag and drop, or by browsing to the location of each item.
It needs to be mentioned that as soon as you add any items to the list, they are automatically locked, without any additional action on your part. This means that neither you or any other user can access them when trying to open them using their default apps (you can however mark them as Unlocked within the main window of LockMyFiles, then revert their status to Locked when you are done working with them).
While its GUI is intentionally minimalist, it is also somewhat plain and lackluster, missing any elements that might help the app stand out in the crowd.
Also, if you want to protect numerous files, you are likely to end up with a large list, so having a way to group them into categories (and sort them by format, for example) would save you a lot of time.
All in all, LockMyFiles has the potential to become a really useful tool, but for now, it still comes with a few rough edges. Nonetheless, having your most valuable files constantly locked away and kept safe from nosy colleagues can only be an advantage, especially when using a shared computer.