Yes, just give a gentle nudge a little at a time to progress your work up your needle.
and as far as how tight...
Never so tight that you can't work your needle into your loop, or have it strangle the band on your circular so you can't nudge your work forward.

The tightness is a sensitive thing, as it can also screw up the gauge of your project.. Be sure to check your gauge.

After a scarf or two or even a wash cloth or two... you get a feeling for your gauge and how it needs to be.
Remember when changing fiber types cotton is different than wool, is different than silk, is different than acrylic.