I'm using tracing paper to transfer the sleeve pattern block onto a working pattern that I can hack into. I won't cut out the pattern blocks until I know that they're good to use - that way, I can amend them if necessary. Once I've cut out the traced sleeve, I can start cutting it up.
Here you can see that I've sliced the sleeve lengthwise into four pieces so as widen it ready to be gathered.
And here, I've sticky taped the pieces, with 1 cm between each, to some more tracing paper. I've traced around it, adding 1 cm or so at top and bottom. You can just see the new cutting line.
I can now cut out the three pattern pieces and I'm just about done. I'm not going to add seam allowances to the pattern - the European patterns that I mostly use come without seam allowances so I now prefer to just add the allowance as I cut. I also won't try and make a pattern yet for the neck binding - my plan is to sew the t-shirt together, find some binding fabric, and then working out how long the binding piece should be.
Next step - making the t-shirt! Sewing with jersey fabrics is something that I was scared of doing until very recently, and I was pleasantly surprised to find that it's easier than I thought. Well, it could hardly have been harder... So I'm going to do the t-shirt as a kind of tutorial.