Here's a gauge/sizing tip:
When you begin a garment that's constructed in pieces, make the size your gauge swatch says you should and then CHECK your gauge BEFORE you get to any size-specific elements. THEN, if necessary, change to a different size.
For example, I'm making Athos
. I began on the back using my gauge swatch of 4.5 spi, so I CO for size S. When I got to the sleeves, I discovered that my gauge was actually 4.75 spi. I'm doing the sleeve decreases so that my bind-offs and decreases bring the stitch counts to the size M stitch counts. Then I will begin the FRONT on the size L. When I get to the sleeves, I'll switch so the bind offs and decreases will bring the stitch counts to match the M so the front and back will match at the shoulders. This way, it's big enough around the middle, the side seams are slightly toward the back (no big deal), but the shoulders will match and it will FIT! I've done this on other projects and it turns out beautifully without a lot of re-knitting.
I hate it when my gauge swatch lies, but when it does, I can (usually) still make it work!