Salome Ellen did not actually ask me for any tips on making adult sweaters, but I am going to offer some anyway. If you have never made a sweater for an adult and you would like to make a sweater for an adult, here are some ideas for you:
First, consider your materials carefully. I recommend Aran-weight wool. The Aran-weight part will make for faster knitting, because there is a whole lot of surface area in any sweater that will fit an adult. I have made adult sweaters with 22 stitches per square inch and adult sweaters with 56 stitches per square inch. One of those requires more resolve than the other. I recommend wool because it is forgiving. A sweater back presents a large expanse of stockinette, and minor variations in your gauge will be more apparent in yarns that are not made from pleasantly sticky animal fibers that bloom up nicely when blocked.
Second, consider a top-down pattern. You can check fit as you go with a top-down pattern, and fix any disasters before it's too late. I've only used Ann Budd's book for one project, but I'm sure I'll do so again in the future. The spiral binding is a particularly nice touch.
Third, don't do raglan sleeves. The standard raglan sleeve recipe leaves too much fabric under the arms, so you wind up with a garment in which you could stash an extra breast or two if you found them lying by the side of the road. (Here again we sample the weirdness that arises when Jamie attempts to blog in haste. I am zipping through this post quickly, see, so I can do my yoga video for the day. In the pursuit of inner peace I am going to natter on about dismembered body parts. Right. Moving on now.) I like a nice set-in sleeve myself.
This is really a postscript to the first paragraph even though it is the fourth position counting from the top, so what does that make it? Firth? Fourst? I suggest that you not succumb to the variegated yarn temptation and even that you think carefully about the semisolid yarn temptation. Fabric made from variegated yarn will have a serious "made by hand" look to it. The world is full of beautiful variegated yarn; I get it. But I have come to think that it is most suitable for patting fondly in yarn shops and then returning to its hanger. Semisolid yarn will be less emphatic in its "my mother made this for me" proclamation, but it will proclaim nonetheless.
Fifth, I find sweater knitting most fun when I can clear the decks and just make that sweater. Long lingering sweater projects create all kinds of avoidable hassles. Moths. Lost materials. Surprising changes in gauge from one year to the next. Bulky sweater pieces lying around in overstuffed project bags. My favorite way to knit a sweater is to find a pattern that totally sucks me in and then run with it. There are so many fun ways to make a handknit sweater distinctive and beautiful. (I still love this back detail.)
But also, sixth, don't settle. If you aren't happy with that bound-off edge it will bug you every single time you wear the sweater. Ask me how I know. A sweater is a substantial investment of time and often of money. Leave time to get the finishing right.
Seventh, on the subject of just-right finishing, I have a BO recommendation for you. A knitted BO will be too firm for a buttonband but Jeny's Surprisingly Stretchy BO will be too floppy. Instead of going up a needle size I have just discovered something that works nicely: I bind off the knit stitches traditionally and use JSSBO for the purl stitches. I avoid the awkward reverse YOs and the floppiness at the same time. Try it and tell me what you think!