Whatever you make will be truly appreciated by your charity, but I write this as someone who joins a lot of squares, so it is a little bit for making my own life easy! Please don’t be put off if you’re a novice, we can overcome all of these things, and we’d rather have your squares than not!
When you’re making squares for charity or for any joint blankets please think about the following:
Use the size hook or needles specified. Especially where blankets are hooked together, it really helps if the stitches are close to the size of the hook used for joining and for the border - only if your tension is incredibly tight or incredibly loose should you go up or down by 0.5mm
Use the yarn and colour palette specified, where there is one…
Sew in your ends really, really securely. All your work making squares will be worthless if it falls apart. Make sure your ends are at least five inches long, find a firm part of your work that will secure the end, wiggle your needle through the back of the work two or three times going back over your sewing to secure the end. If possible leave the stitches on the edge of your square free from the sewing in, this makes joining the squares much easier.
It is better that the join is a tiny bit bulky, than a recipient, who may not have the means to repair it, finds it unravelling around them.
If you’re nearing the end of your square, measure - after a few rows if you’re a knitter - if in doubt, always make slightly under the size than over the size specified.
When joining a blanket it is always easier to slightly stretch a square or even to add a border, rather than trying to squash in a too big square that will cause rippling and ruffling. The notion that an oversize square will compensate for a smaller one doesn’t work, blankets are generally joined in straight lines in each direction and this doesn’t allow for jiggling around different sizes squares
Don’t wash or block your squares, this makes it really hard to get the hook through for joining, most squares will pull flat when joined anyway. Also as you won’t be washing your square, do try and keep your cats and dogs and tea and wine away from them too!