Help!  My prefolds/flats are leakin' & blowin' out in the legs...

On the PFs, you can get a tighter fit through the legs if you fasten the pins/snappi lower along the back corners (you may need to flare it open a little wider to do this & use a little more of the rise so that the back can sit a little higher).  In the pics on the prefolds how-to pages, you'll see I fastened the snappi right over the PF's back corners...  you'll want to try fastenin' 1-2" below that.

Also, try tuckin' in the legs just a little bit~ maybe 1/2" to still get the dam effect, but leavin' a slightly longer leg length.  If you're usin' a doubler, lay it in the PF before you do the initial tri-foldin' (if you lay a doubler on top after you trifold & flare, it covers up the poo pocket).

On the flats, skip any extra steps to trim the fit.  Use two pins fastened vertically on each side (either just inside or outside where your baby's hipbones are, rememberin' that lower fastenin' = tighter legs).  The idea is to pin the outer edges of the center panel to keep tension on it, so it can't bunch or sag in the crotch and create an escape route in front.  Tuck in just a bit around the legs (again, just enough to make a dam, but leavin' it a little long).

If you are usin' the origami fold, and your baby has skinny legs or boy parts that are fallin' out, you'll also want to either fold the soaker panel to make it wider (fold it twice instead of three or four times) or fold down a few inches in the front (so that the V shape of the wings makes for a slightly wider front panel and encircles more of the legs in front).  Otherwise, you may want to consider usin' the prefold or the kite fold.

Help!  My prefolds/flats are blowin' out up the back...

On the PFs, make sure that if you're usin' a doubler, you lay it in the PF before you do the initial tri-foldin' (if you lay a doubler on top after you trifold & flare, it covers up the poo pocket).  If this isn't the culprit, you can try either tuckin' in the back just a little bit~ maybe 1/2" to get the same dam effect as the legs, or you can fasten the pins/snappi lower along the back corners (you may need to flare it open a little wider to do this & use a little more of the rise so that the back can sit a little higher).  In the pics on the prefolds how-to pages, you'll see I fastened the snappi right over the PF's back corners...  you'll want to try fastenin' 1-2" below that.  

For flats, try foldin' down 1-2" inches in the back both to create a dam and to give you a sturdier band to pin/snappi.  If you are already tweakin' the fold to make it bigger~ meanin' there is only a single layer of fabric along the waist, you may need to move on from the prefold or origami to the kite.

In general, if you aren't usin' pins, you may want to give 'em a try~ when fastenin' pins vertically, you get a snug band across the back instead of just a snug line.