Right, so once you've chosen the pattern and the yarn (or perhaps they've chosen you?), let's start with the basics: (1) Katherine, read the pattern. Properly! Do you have all the required yarn and tools? Does it make sense to you? (As you've never been on a long train / car journey, more excited about the trip and its promise of all that unadulterated knitting time than the destination, only to find that you don't have a cable needle? Or the 2g of contrast yarn required? Or there's a new and unusual knitting instruction that's without a full description in the main body of the pattern and you don't have internet access? Oh no, never.)
(2) Continuing with the pattern, but this time in relation to non-Katherine mistakes, check on-line for any addendums / errors. These occur more frequently that you might think so it's best to know beforehand than to try to correct later on. (Because hours struggling to make something fit that mathematically won't, now that's not in the least bit frustrating.) Check the designer's website plus other sources (e.g. Ravelry) where the pattern has previously been knitted.
(3) Check the measurements of the finished piece. Do they suit you? After all, what's the point in spending all of that time producing a hand-knitted garment when, say, the sleeves are too short? My dress-making tutor encouraged us to take all our "vital measurements" and then keep them in a sensible place for easy referral whenever we started a new project. That may work with those of you who rarely change body shape, but not me. However, it's not hard to slip a tape measure around the important areas and keep note of the numbers. A little thought and perhaps an extra ball of yarn, that's all it takes.
(4) Note the shoulder shaping: Would the pattern benefit from some short-row shaping / double needle cast off?
(5) Note where the increases / decreases are worked: Are they a feature of the garment or hidden in the seam? Are you happy with that specific feature of the design?
(6) Consider including selvedges to strengthen your fabric.
(7) Knit a tension square. (Yes, that old sausage!) It's my new year’s resolution (okay, it's April so let’s be all Christian about when the New Year starts) and I'll be keeping the squares (if the yarn isn't required for the garment) to make a blanket (erm, really?) or just to embellish my knitting note book.
(8) On completion of a slightly tricky / new / unclear section of the pattern, check your knitting against that in the photo, before you cast off. (For example, does your neckline look anything like that worn by the model?) If not, why not? (And is your version really better?)
And now some tips for completing the project:
(1) Do not look at any other pattern books or yarn. (Obviously your subscription to your favourite knitting magazine doesn't count!)
(2) Go to knitting club and ask your friends to "encourage" you to finish. (No, this won't ever be as annoying as your supervisor asking for progress reports on your thesis.)
(3) Set yourself such short deadlines that you won't have time to look at anything else and publicly share the insanity of your decision making – there's nothing like maintaining your knitting "honour" to keep those needles clicking.
(4) Never, ever, offer to knit your husband a jumper.