I start with picking up extra stitches under the arm. Very rarely, does a pattern, in my opinion, have you pick up enough stitches under the arm, which results in some extra stitches left or a bit of looseness under the arm. I, also, for my sleeves, almost always go up a needle size or two from what I have used in the sweater yoke. It depends on how I like the fabric that is created with the larger needle. Generally, the fabric doesn’t change enough for me to mind.
In my notes on my i-phone, I have the measurements of when I need to start decreasing my sleeves which is right about one inch above the elbow.
Using the handy dandy website from yesterday, I calculate the decreases I need to make, to get to my very small wrist. (Why couldn't the rest of my arms be as small as my wrist measurement?). The website tells me exactly how to achieve nice decreases.
Right before the rib, I make sure that my stitch count works with the rib count needed and then go to a smaller needle size to cinch in the wrist.
And voila, I've got the perfect sleeve for my arm!
Hope this helps you to have better sleeves for your arm. You are in control of your knitting!