I try to avoid most vehicle conflicts by choosing routes and times with less traffic. That reduces the necessities to take the lane when only a single lane is available. And I try to delay folks behind me as little as possible.
After having commuted and ridden recreationally on and off since the 1970s, I've found that what works best for me is demonstrated in this video.
When I do take the lane, I am very assertive about it. I make it clear through lane position and signals that the lane is not up for sharing and the driver must choose to wait for an appropriate time to pass or deliberately run me down. There is no safer way to ride some routes in my area, particularly where highways merge with otherwise quiet access roads and lightly traveled rural highways. It's never a good idea to be timid or hug the side of the road with merging traffic -- that's a recipe for getting pinched or run over by big rig tractor trailers or rookies towing boats or equipment trailers.
There are dozens, perhaps hundreds, of videos on variations of vehicular cycling. But this one seems to summarize it best without digressions into emotions, politics, etc. It's just a demonstration and explanation of an effective technique.