How do I know when it's Done?

How do I get from this…

to this?

I get this question, every time I speak on cooking.  Usually people are looking for a time in the grill or oven.  With the exception of fish, the way to think about this issue is not time, but internal temperature.  I suggest a digital meat thermometer.  They're cheap, fast and accurate.  Professionals often use the standard stem thermometer which can be quickly calibrated in a glass of ice water.  And I don't suggest gadgets that have a rare, medium and done setting,  just take the extra five minutes to remember this guide and you're on your way to knowing the nature of raosted grill meats.  Soon you'll just get a feel for where your foods are in the cooking cycle.
Use this guide as a starting place then adjust to your preferred doneness!  (Warning,The FDA suggests much higher target temperatures to avoid bacterial contamination.)   

Mad Coyote Joe's Grilled Meats, Fish and Foul, Target Temperature Guide.

Chicken

            Grill indirectly high heat, target temperature 165°f at the thickest part of the breast and thigh

Duck

            Grill indirectly, high heat, target temperature rare145°f, well done 165°f at the thickest part of the thigh breast.  If smoking or roasting suspend over a water bath.

Lamb

            Chops; grill directly, medium high heat, target temperature 145°f center of the chop

            Leg; grill indirectly, medium high heat, target temperature 145°f rare, 165°f well done, test at center of the leg

Pork

            Tenderloin and chops, medium high heat, target temperature, rare 145°f , well 165°f at center

            Roasts,  the old guys say, "low and slow", roast or smoke at 250°f to 325°f-target temperature done at 165°f but fall apart tender 192°f

Beef           

            Tender cuts (non-locomotive); Steaks, tenderloins, fillets and tender roasts like tri tip, quick sear, high heat indirect finish, target temperature rare 124°f, medium rare 128°f, medium 132°f, medium well 136°f, well 140°f

            Tough cuts; brisket, chuck roasts, pot roasts, long slow cooking, sear then braise, moist environment, target temperature, 192°f

Fish

            Direct grilling medium high heat, 10 minutes of grilling for every inch of thickness.

Allow all grilled meat and poultry to rest for at least 10 minutes after removing from heat.