|M1L/M1R on the left side M1R/M1L on the right side outlined my markers (Click on the photo for a larger view)|
In every glove class I teach we always have some discussion regarding the positioning of MIL and MIR increases on either side of the thumb gusset. The six hour version of the class has students working on a mini sample to test as many glove making skills as possible. We work the glove in stocking stitch using a M1R increase on the left and M1L on the right of the thumb gusset. I've looked at a lot of glove patterns to check what increase is recommended. Many patterns avoid the issue of which increase to use by giving the instruction as increase 1 or M1 with no specifics as to the intended increase. Pattern standards are shifting and many tech editors recommend that designers be more specific with these details. I see M1L and M1R (worked in that order) fairly frequently and on occasion I see them in reverse order. I have had the best results with the order in the right half of the photo above (M1L then M1R on either side of a central stitch). It is a tiny bit bit smoother for me. If you look at the left side of the photo, one leg of the stitches is slightly out of alignment. In some stitch patterns this might look better. The best increase to use in a specific situation is always going to be dependent on a number of factors, including the yarn and needles being used, the stitch patterns used and the knitters individual knitting style.
In the case of M1L and M1R, the increases do have directionality but it is not as prominent as the slant that we see on the paired decreases k2tog and ssk.
|M1R on the left side M1L on the right side, the new stitch is worked just above the marker. (Click on the photo for a larger view)|
The trick I use to remember each one is:
M1R is worked by using the left needle, to lift running thread between stitch just worked and next stitch, from back to front, and knit into front of resulting loop. (BFF). I keep them straight in my mind by adding the phrase "my best friend forever is always right"
There was a recent thread on this topic on Ravelry here. It's an interesting discussion because the posters look at what happens when you are working on the right and wrong side of the work. They question, is the R and L of the name referring to the direction of the lean or the placement of the new stitch in relation to a central stitch as well as looking at the order of execution of each increase.
The best way for you to understand the nuances of this discussion, is to knit a sample and watch carefully as you work each variation, then decide what works best for you and for your specific project. If you read the thread, note that different knitters get better or more pleasing results in different ways.
You can see my Glove series of posts here.