Most of us are inundated by the discards of tools promising to make your sewing easier. I myself have a whole box of such devices (even though I generally dislike gadgets). But when it really comes down to it there are only a few items that I always go back to. These are my top 3:
1) The slivered ends of bath soap. Yes, you heard me correctly. This is my go to for marking buttonholes, darts, tucks and anything else that requires some guidelines. Now this is not fancy stuff, and it works mostly for darker fabrics. I love it because I just apply some steam from the iron and, voila! it disappears. If your soap is a little more stubborn then a little water will wash it away. I use my Dove soap until it is almost paper-thin. Perfect for sharp markings.
2) Horsehair tape or band-roll (the jury is still out on the official name as I have consulted those who order this for bulk and still no one knows). I will hail the merits in an upcoming hem tutorial. I tried all sorts of fancy rolled hem feet and they were a pain and a half to get going. Now this is not necessarily the fastest method, but for me It gets the job done the nicest.
3) Sleeve ironing board. When your garment is nearing completion, and if you make small items like me, this fits easily into sleeves and pant legs so you can press open the seam allowance without applying permanent press marks to multiple layers. I use this more than my regular ironing board. They also come in different widths.
What are your go to tools?