What are the signs of a successful hair transplant? (Photo)

It can take 6 to 12 months after surgery to see results.  If you are concerned it is best to contact your doctor.  Signs of a successful transplant is when you see the results and you are happy with the results in 6 to 12 months.  There isn't much you can tell in 14 days.

From the picture, you have a little scabbing in the frontal area where it looks like the density was concentrated highest and it looks like you've held onto many of the transplanted hairs above the surface of the skin at 14 days. Aside from the scabbing, the grafts look nicely distributed. I would check with your surgeon about the scabbing in front just to make sure there isn't something that needs to be monitored.
Ultimately the success of the transplant is determined by whether or not it accomplishes your goals once its grown in. You're in the initial healing phase now. You will go thru a period of no growth, then incremental growth until the final results at 12-16 months. It's a lengthy process. Around 6-9 months you can start seeing a visual change since the hairs will be growing, getting some density, and length to them. To determine the success, I would stand back and look at your appearance in 12 months and compare that to where you started. If you look and say, I'm really glad I did this or I look so much better, its a success. Happy healing! 

The average person gets 80% of the growth in 8 months to styling length of about 3 inches. It varies with individuals, some earlier and some later