There are two that I always remember-

From Allison, Arasmama-

To easily undo serging, pull out the needle threads, the looper threads will come undone easily, and is much easier than seam ripping. The thing to remember is to start out slow & steady! I swear I use this way too often!

Secondly, from Bethan, Scarlet-

To restore stretched out elastic, steam with the iron, not touching the soleplate to the fabric. This works every time! It is especially handy when you are doing multiple rows of stitching on a waistband!

So, what are some of your favorite tips?

Suzanne (blueberry farm ?) maintain your machines when aunt flow shows up :D

Stacy (alipoo) tie on new serger thread using a "surgical knot".

Edited to add: I'm not sure who posted this, but when there is a problem with stitches, vacuum out the bobbin space. This one has been a sanity saver!! :p

Not sure where I got the tips from but here are some of the ones I find useful...

steam press wobbly jersey hems... you know the rollercoaster ones.

I forget who posted it recently but basically it was along the lines of "if someone is close enough to critique your work, they are close enough for a poke in the eye." This reminds me that stuff does not have to be perfect in order to be beautiful or valuable.

Double needling, I tried it for the first time after seeing it here.

Preshrinking interfacing with the steam of the iron held a short distance above it. I no longer have crinkly awful interfacing after the first wash.

Using a strip of lightweight iron-on interfacing to stabilise wavy zips or really wavy hems.

All Jenn's help with quilts.

Jenn/BonaDea - when serging necklines, start at the shoulder seam instead of the center back. Your start/stop location won't show and you'll have a nice, clean spot in the back (which is handy when you have new labels and want everything to look nice and tidy ;) ).

I've never heard that elastic tip and I was literally just sitting down to try to repair some elastic on a neckline. I'm going to try it right now!

i don't remember who posted it originally, but the high tension gathering method rocks. set your stitch length as long as possible, your tension as high as possible, and sew a straight line close to the edge you want gathered. works like a charm, and I like being able to adjust the gathers before attaching them (vs. the differential feed method or the gathering foot method).