Lauriana used her serger to make a mock-flatlock hem. It's stretchy, sturdy and doesn't require a coverstitch machine or twin needle. I completely forgot about this technique until she mentioned hemming her amazing twist top that way.
I first learned this technique from my Bernina dealer* when I bought my Bernette 334DS (made by Juki). She showed me how to do this with 2 or 3 threads. The manual only shows how to do this with 2 threads (lower looper and one needle) and calls it "2 thread flatlock" (page 21). They recommend loosening the needle tension and tightening the lower looper tension.
The Serger Idea Book from Palmer/Pletsch shows how to flatlock with either 2 or 3 threads on pages 18-20. They recommend lowering the top thread tension and increasing the lower looper tension as far as possible. It's an old book, but full of useful information. Used copies can be purchased on Amazon for $0.01 + shipping.
If you are having trouble with your serger, or are just learning how to use a serger, I highly recommend The Ultimate Serger Answer Guide. It helps you diagnose and solve most serger problems (or refers you to a dealer for more complicated timing ones). Used copies are $1.98 and up.
Singer Reference Library Sewing with an Overlock teaches serger-specific sewing techniques. $0.01 + shipping. I expect the updated The New Sewing with a Serger will be just as useful.
Serged Garments in Minutes explains serger construction order and techniques. $0.01 used from Amazon.
Sew Fast, Faster, Fastest is not serger-specific, but explains different construction techniques and sewing orders. You can see the trade-offs in the name of saving time and decide which level is right for you. Most cheap clothes are sewn with "fastest" techniques, which means an irritating seam up one shoulder and across the neckband on t-shirts. I would take the extra 2 minutes to use the "faster" (better RTW) or extra 5 minutes to do the "fast" (designer) technique instead. But, you may decide differently. The nice thing about this book is that it doesn't tell you what is right or wrong. it just explains different techniques clearly to give you the knowledge you need to make your own decisions. It's also available used for as little as $0.01 through Amazon.
None of these books include the words "new" or "modern" in their titles or show super skinny models wearing painfully hip or "retro" clothes. But, they were written by professional home economists back in the day when home economics was taken so seriously, smart women went to university and earned graduate degrees in home ec. These authors *really* know how to construct clothing and how to teach.
My only caveat is that, 20-25 years ago, when these books were written, rotary cutters were not widely used in home sewing yet so the books don't mention them. (I use rotary cutters, but others swear by pins and shears. Use whatever makes you happy.)
I took home ec in 8th grade, but my daughter doesn't have the option. That is beyond sad, but I will give that its own post another day.
* Yes, Berninas appear to be overpriced relative to competitors. But, keep in mind that the prices include dealer training. You should get 6-24 hours of training in how to use your specific machine in a small group setting (or one on one) with your dealer. When I purchased my Bernina Aurora QE during an illness and forgot everything I learned in class, my dealer let me repeat the classes as a refresher after I recovered without extra charge. You *do* get something of value out of that extra $$$. They can only afford to keep their in-house instructors by paying them like professionals and charging you $$$ to pay their salaries.