A great example of this reflection, though fictional, is O'Henry's "Ransom of Red Chief," excerpted below.
IT LOOKED like a good thing: but wait till I tell you. (1) We were down South, in Alabama Bill Driscoll and myself when this kid- napping idea struck us. It was, as Bill after- ward expressed it, "during a moment of temporary mental apparition"; but we didn't find that out till later. (1) There was a town down there, as flat as a flannel-cake, and called Summit, of course.(3) It contained inhabitants of as undeleterious and self-satisfied(3) a class of peasantry as ever clustered around a Maypole. Bill and me had a joint capital of about six hundred dollars, and we needed just two thousand dollars more to pull off a fraudulent town-lot scheme in Western Illinois with. We talked it over on the front steps of the hotel. Philoprogenitiveness, says we, is strong in semirural communities; therefore, and for other reasons, a kidnapping project ought to do better(2) there than in the radius of newspapers that send reporters out in plain clothes to stir up talk about such things. We knew that Summit couldn't get after us with anything stronger than constables and, maybe, some lackadaisical bloodhounds and a diatribe or two in the Weekly Farmers Budget. So, it looked good. (1) We selected for our victim the only child of a prominent citizen named Ebenezer Dorset. The father was respectable and tight, a mort- gage fancier and a stern, upright collection- plate passer and forecloser.(3) The kid was a boy of ten, with bas-relief freckles, and hair the colour of the cover of the magazine you buy at the news-stand when you want to catch a train. Bill and me figured(2) that Ebenezer would melt down for a ransom of two thousand dollars to a cent. But wait till I tell you. (1)
Some people would call this amount of foreshadowing heavy handed, but it not only works here, it also emphasizes the moral vacuity of our protagonists and sets us up for the character of both Johnny and Ebenezer Dorset, who are fitting antagonists.
The passages marked (1) show simple foreshadowing--wait till I tell you. The passages marked (2) are verbs which mark uncertainty--we thought it was a sure thing...but it wasn't. The passages marked (3) are either sarcastic, showing that things are not as they appear, or revealing of double-edged details--have you ever met a kind or sentimental forecloser, who "melts"?
How can you use this in your story? Exactly the same way.
- Add your current feelings. Consider again the idea of writing memoir as fishing--you always have that reflection of the world above the water on the surface between you and the fish. What are your feelings now? Feel free to write them down in snippets as the story plays out. You may need to revise, but there are very few who don't, so don't worry.
- Revise your verbs. Choose "might" instead of "will," "could" instead of "can." Show us the uncertainty.
- Follow the double-edged details. If you are about to be surprised, then make sure you seed the story with details that will help us see that the possibility for surprise was indeed there. Sometimes this happens the second time through, and that's okay.