One thing that helped my daughter was when she had a really strong impulse to cut she would draw it or sketch it and the impulse would seem to pass with the action

Putting an elastic band on my wrist and pulling it as hard as I can and snapping it back on my wrist, doing this over and over until the urge stops x

I wish I had an answer for this one - but I struggle with it as well. For me, it's making sure I have nothing around me that I use to self harm, and when the urge is to where I can't stand it anymore I go down to the beach and go for a walk and try to think of all the reasons why I work at not s/h ... that works somewhat - but this is a struggle for me as well so not a big help I'm sorry