I have found that the simplest way to address anxiety (for me, personally) is to intentionally focus my thoughts on what I want to have happen vs. what I don't want to have happen.

If I do it with enough detail and really paint a picture of a positive outcome, it not only relieves the anxiety but it seems to increase the chances of things working out the way I want them to.

And it has helped a lot, to do as you suggest, and understand where the anxiety is coming from. If it's past events, I can always remind myself that we all tend to jump to negative conclusions automatically based on past experience, but we can choose not to dwell on them.

I like to say to myself "That was then; and this is now." That usually helps me let go of the old stuff. It still pops up, but the more I remind myself that it's not a helpful thought, the less it happens over time.