Could anyone offer me some advice on this fitting issue please

[Mama likes to make]

Hi. I'm attempting to make a pair of denim jeans (well they will be pull on as she is only nearly 4 and needs easy up and down) drawn from a pair she already has that fit her well.

This in itself is a challenge as I won't take them apart as they still fit and it's rare I find trousers that do for her 

I've run up a pair in some fabric I have lying around and I'm happy with the legs but the waist and crotch have come up too big. I've marked on them roughly where needs to come out around the crotch but I was wondering what's the best way to take this volume out please?

Thanks a million 

[BrendaP]

If the marked lines are where you think the seam lines need to be then stitch the seam together along those lines, and trim some of the excess away then try them on.

Assuming that you make the new seam at the same distance in all the way along CF and CB seams right around the crotch that will reduce the waist circumference by quite a bit.  It looks as though the new seam lines are about 15mm in from the original seam - if that's the case then the waist will be reduced by 4 x 15mm = 60mm. 

If that is too much you will need to taper the new seam line from crotch to waist so that at the waistline only the required amount of reduction is made.

[DementedFairy]

I would start again, and try for a better rub-off from the originals- if they fit her well, and the toile has come up like this, it seems way out.

You need to draw a straight line on a piece of toile fabric, and pin the straight line down the side seam of the jeans.

Then work on JUST the front, and smooth the fabric round, pinning as you go, until you get to the CF seam, crotch seam, and inside leg.  pin like hell, then use a marker or pencil to draw those seam lines in.
Unpin the front, and repeat for the back.
Also mark waist line.
Ignore pockets etc, add them afterwards.
 [Don't try for both at once, it's too 3-D!

Remove from the original, lay out flat, and straighten that side seam line again.

Spread your fabric out, and neaten up the pencil lines.

Cut along your new lines, and hey, presto!  A pattern [without seam allowances of course.

This should give a very close copy of the original garment

[Mama likes to make]

Thank you both so much for the help.

I think part of the problem has come from the difference in the front of the actual trousers compared to what I want to make. The actual trousers have a fly which I don't want. I didn't get a chance to look at them again today as we were out all day but I'll have another go again tomorrow hopefully.

[DementedFairy]

The method I suggested will still work- simply ignore the fly, and mark CF line only.

[Mama likes to make]

Thank you. Hopefully I will get at them again today. I redrew her leggings pattern as well so she should be well covered for the bottom half!!!