I used to have a few shirts that I really liked but which did not fit especially well around the waist. They were bought in the days when I knew a lot less about fit and cloth (hard to imagine, isn’t it?), and while the neck, shoulders and sleeve were fine, the cut was simply too full from the chest downwards.

Such were my frustrations, I may have thrown them out. So instead I decided to try and sew my own darts into them, to narrow the waist. If I messed it up, I could just throw them away anyway.

My first attempt went surprisingly well, but there were a few lessons learned. I should have tried a couple of variations on the shape and size of the darts before I sewed them in. I should have been a little less cautious on their length. And while they held up very well in the wash, I learned it was worth sewing as tight stitches as possible.

I think I’ve now got a pretty good system, and all those shirts have been darted, worn and washed several times, to pleasing effect. I could have had it done at a tailor, but not being in essence a practical person, it is very satisfying to master a skill such as this. And it probably saved me £100. Here is my step-by-step guide to putting darts in your shirts. It is not that hard, and very satisfying when completed.

1. Lay out your shirt on an ironing board. Pinch the material in two places, roughly where your waist would be and a couple of inches in from the seam on either side. Start with a fold of a couple of centimetres, folded out towards the seam. Iron that patch flat and then fold the material above and below, pulling the material away gradually so it forms a crescent.

2. Pin both folds with three pins or needles each, to keep them in place.

3. Try the shirt on, being careful that none of the pins point inwards. Assess how suppressed the waist is by pulling the sides away from your skin, and try sitting down, stretching etc.

4. If the fold needs adjusting, take it back to the ironing board and fold the material more or less. Also, if you feel the dart could or should be longer, narrowing more of the shirt’s body, then extend the crescent above and below.

5. Sew the fold in place, starting with a few stitches in one place (on the inside of the shirt so it doesn’t show) and then sew smallish stitches, in and out up the fold, and finishing in the same way.

6. Use white thread unless the shirt is one block colour – and look closely, most colours are a mix of a darker colour and white.

7. Don’t worry if the stitches seem far apart. They will hold up well – and they don’t have to be as tight as the ones that construct the shirt itself. (You could of course do this on a sewing machine as well if you have one. I don’t.)

If you find it hard to iron the crescents (I found it the trickiest part) you can always start the fold halfway down the back of the shirt and just carry it on off the bottom of the tail. This will create a flap on the bottom, but if you have your shirt tucked in most of the time, this won’t be a problem. I found this particularly useful on a Ralph Lauren blue oxford, which although “custom fit” was still far too broad. The thicker material made it hard to fold accurately.

I’m sure some of you are proficient sewers, and all this is the equivalent of teaching your grandma to suck eggs. I’m sure others are horrified at the idea of amateur tailoring. But I found it very satisfying (a step up from hemming my trousers) and I encourage you to have a go.