Navigating around London or other city?

Are services like Google Maps, Cyclestreets the best for figuring out routes, or is it more about trying different routes to see ones that are better for the cyclist or actually asking friends / other cyclists advice about routes?
I'm doing a little survey for a cycling safety project I'm working on - would be really helpful to hear your views!

A combination of the two, I find.

If you live in a city, explore it.

Ride around and experiment, get lost, get found, mix it up. have fun.ride your bike, ride your bike, ride your bike.
Simples

I find if i follow my phone I don't remember a route. Muddle through, memorize a route or use a paper map and I remember it.

Use a Garmin.

While on foot i picked up a TFL paper map on rental bike locations, this will most likely be my main guide while riding.

I won't be going to work, but tourist, so multiple destinations, start point would be constant at Kings Cross, this would also be finish point to get train home.
Starting on rental bikes as no London spec locks, and only have to find a docking station, not worry about locking my own bike up......will it get nicked.....will it be moved if locked in wrong place.
I would plot a route online, maybe mark on paper map. You will see hidden routes as you travel, quiet paralell side roads, cut throughs, short cuts, get off go up/down steps things like that, routes that maybe a program won't account for.
After a few trips i should have a core knowledge of around Kings cross, and build on that.

As with the others, explore, sometimes getting lost is a good thing and the maybe direct shortest route (we find this at work with sat nav) is not as good as indirect longer route.
I am not a tech person, and prefer a map as you get an instant area overlay that is lacking on small screen devices.
If i was working in London, i would go online and route plan, then add in variations, explore other options on the fly.