I find the thing to do is to read lots of TRs, look at lots of photos, tell yourself if you don't like the look of it you don't have to do it. Make sure you have an alternative route in case when it comes to the point you want to avoid it.
Then go. I find once I have made my plans, it often isn't as bad as I am expecting. And if it is, I have a nice alternative walk.
I do find, however, that I get better with practice. At the end of the summer I can often tackle things I would have avoided earlier in the season.
And remind yourself that a fear of heights is a perfectly sensible reaction to the effects of gravity! There's no shame in it.