internet strangers putting out advice is only going to help to a certain extent, but to answer directly to concerns about traffic dangers (legit, real life ending possibilities) it comes down to being situationally aware at all times.

Riding in urban environments is great practice for this, and going from your flyboy moniker, its like any complicated, potentially dangerous activity--being realistically aware of the dangers, being aware of how to reduce and manage the dangers--specifically with biking stuff like having an excellent mirror system, using common sense of which situations can possibly end badly and therefore taking to the side of the road on the grass (Im referring to specifically a truck coming towards you, a truck coming behind you, narrow road, no room for trucks to move over if the timing means all three of you are at same point)

being situationally aware, using common sense and always thinking ahead a bit, just like in flying or whatever, makes a huge huge difference.

one does learn by doing it to react better and judge situations better, so if you need to ride more out on real roads, do it, it will help.
If your bike handling skills and comfort level need improving, more riding out on real roads will improve this also, its like any activity, the more often you do it, the better you get.

more than that, its up to you to know yourself and what you are comfortable with and your capacity to adapt and be smart.

doing little weekend trips loaded are great for getting used to stuff, and are at least more easily fit into regular life with work and family.
all the best