I use Bleach to clean my drain the minute it looks even slightly dirty....It will clean also away and Germs.
I use a 'magic-sponge' to clean the whole sink every day.With a dose of boiling hot water at night.
I clean my kitchen sink after every time I wash the dishes. I don't like the look of dish washing detergent scum rings around the interior of the sink and detergent bubbles and left over crumbs that accumulate around the plug hole. I'm pretty fussy when it comes to the appearance of my kitchen sink.
Literally every time I wash up dishes in the kitchen sink.
I use the remaining washing up water with a scourer so there is no residual scum left.
Then once per week flush the drain with drain cleaner.