Hi and welcome, I am a Newbee of six weeks
I answered this question a few days back,
Always use the sides of the fingers about an eighth of an inch below the nail (the pads hurt)
Some people prick each of their fingers both sides in rotation until they have used all 20 sides then start again
I try to avoid the thumb and the forefinger because these are the ones used to pick up small object, as I found out yesterday, I type with my two forefingers, and hit the space bar with my thumb
Having said all this I only use the little finger of mt left hand, it seems to be the least sensitive even thogh it does look a bit like a pin cushion (I test eight times per day)
Hope this is of help
Regards
Mart