As to telling exactly where you hit, the arrow tells the tale.

Bright red blood in spots or sprays usually means a muscle hit, which is bad news (usually).

Dark red blood usually indicates a liver hit, which is good, but give a little time.

As to tracking, the best advice I can give is GO SLOW! I have tracked a heck of a lot of wounded deer for people, and have learned that you can infact track a deer when it stops bleeding, but you have to get on your hands and knees. And always mark your track! Knowing where you have been is as important as knowing where you are going. Wounded deer like to head for water, so try and determine exactly where the deer might be headed. Look for spots along the way that look like a deer would travel. If there is a deer path...thats usually a good indicator.....

Also, don't just look for sign on the ground. Lots of times, espeically in thick cover you can find blood on knee/thigh high foilage where the deer brushed up againest the vegetation on the side of the path.

Again, I cannot stress enough the importance of going slow! And nothing is worse than someone who thinks they know what they are doing and goes charging ahead and scuffs up the leaves on the trail....