I am currently reading Deep Work by Cal Newport. Herewith two quick Firefox hacks to help reduce distractions and hence the temptation towards shallow work.
Firstly customize the new tab page to show only search (instructions); in short there is a gear icon in the top right of the new tab page, click on it and turn off everything except search.
Secondly set the Firefox homepage to about:blank or about:newtab if you would prefer to have a search box. Go to Preferences->General for the place to set the Home page.
It has taken me a couple of days to get used to but I noticed an immediate difference in not having the browser reminding me about all my favourite time sinks every time I open a tab.
If you can’t do this with your browser maybe it is time you made the switch to Firefox?