I believe that the best thing to do is to think deeply about it and explore those feelings. Because it's inevitable, we need to accept and embrace it.

Picture any time before you were born. If it's not scary or sad to think about that, then thinking about a time after you die shouldn't be any different.

If you're worried about the actual moment of transition, it's probably going to be either too abrupt for you to really react to it (accident or violence), or you'll be super tired/unconscious and it'll basically be a relief, like sleep. This isn't a guarantee, but it's pretty likely.

As far as I'm concerned, as long as I can avoid a slow, painful death, it's all good. This is why torturous murders/executions and outlawing euthanasia are the most horrible things that people can inflict on each other-- you're ruining a person's only shot at a good death.