What will I need?

I have noticed that my truck doesnt start right up when it it only about 40 degrees. I have to cycle the key a couple of times but if I plug it in then it starts perfect. So I'm thinking its time to replace the glow plugs but when I do that I want to replace everything else that should be replaced. Im not really worried about checking what works and what doesnt. I figured since Im going to be changing the glow plugs I might as well change other things. Can someone tell me what all I will need to buy to do this job, (besides glow plugs:icon_wink Thanks Daniel