Take off a piece about 3-6 inches long of new growth. strip off the lower leaves and insert into a pot of compost mixed with sharp sand or perlite, or into a semi-shaded spot in the ground. Water well and wait for a few months. This is best done from late summer to mid winter. The cuttings should root during the winter and show new growth in the spring. Ensure they don't dry out if in pots - especially if you have a heat mat or something. Good luck.

If it's a Cypress type conifer or Taxus, yes. Pinus, Picea and abies, no.

I would add that I have always found July, August and September the best time to take cuttings.