My Tricep routine varies from week to week. I always start with a compound exercise, which is narrow grip bench press and then move on to something else.
I start with a light weigh of 100lb for 8 reps and then slowly move the weight up, depending on how I feel. Until I hit my 4th set, which is usually 150lb.
Tonight I went onto four sets of Tricep cable pushdowns, personally, I like these. I suffer with pain in my right shoulder and right wrist which causes me grief with a few exercises. I have to work around this though and find different ways that suits me.
I then did four sets of rope pull-downs. The idea is to pull the rope down straight and towards the end pull to the sides.
One arm pull-downs was next, which is simply a light weight pull down. The elbow is to stay neutral at all time and not to move. This is easier said than done when you are getting tired.
Lastly I threw in some one arm over head extensions to finish off my workout. I chose a light weight, as I had already accomplished my target for Triceps. This was simply a quick bonus at the end.