Get out your measuring tape
I've said it before, and I'm sure I'll say it again: you must measure yourself if you want your knits to fit! I just measured myself, as I do every six months, if not more, to make sure my slog-along pullover was going to fit correctly. Wouldn't it be tragic if my four-month knitting project didn't fit? Yes, it would.
Fabulous Knitting Daily founding editor Sandi Wiseheart made a measure-yourself tutorial that I think is worth re-running. I used Sandi's tips when I remeasured myself, and I found the measurements to be very accurate. Here's a handy worksheet you can use as you take your measurements (it includes lots more measurements you should take, too).
Please note, when you measure yourself, do so in your undergarments. Of course, we couldn't do that in the tutorial, but you'll get your most accurate numbers if you don't measure over anything but your bra, panties, etc.
Here's a little taste of this helpful tutorial, see the Measuring Yourself: Bust, Waist, Hip blog for the full instructions on finding all these measurements.
Now that you're armed with your measurements, you can compare them to the schematic in the pattern you're considering, to make sure that the piece is going to fit you.
For example, if your waist measurement is 35" and the pattern schematic shows that the finished waist measurement is 33" for the size you want to knit, you have to make some choices. You can go up a size, if the bust and hip measurements will work with your measurements, or you can do fewer waist decreases. See how those measurements can help your decision-making?
I hope this helps you get yourself measured correctly. And remember, no matter what your measurements are, all of us here at Knitting Daily think you're beautiful!