My approach is - continue the regular routine. Get dressed for work and change clothes after work is done. Use dedicated computer for work and just turn it off after the work is done. I do have a separate "office" room, so that does help too.

Can't say I'm always successful, but I find that routines like dressing up for work, setting up a dedicated computer, etc. help.

I second the advice to keep the routine. I don't have a separate office at home. What I do after work however is clean up my desk and stash away the company laptop and any other work-related things somewhere out of sight.