What tracking aids, if any, would you suggest I invest in?

A good flashlight is all that I would recommend.

Ditto on the flashlight. There is some stuff that you spray to find blood drops but I have no experience or know anyone that uses the stuff.

And toilet paper for blood trail marking! It will disentergrate so you don't have to back-track and pick it up!

Not to mention it is a handy thing for other uses as well.

Flashlight, trail marker of some type and a GPS can be good if you have to back off or your in the thickand need to determine the best route(s).

I have found that when using flash lights that there will be shadows that will cover up samll spots of blood. I use a lantern, I have one that was made for several years but I cannot find them anymore to buy another one. I have used a colman lantern and that works good to. Since the lantern glows and doesn't shine the blood will stand out more and the shadows aren't as bad either. Try this next time.

Get yourself a copy of the guide "Finding Wounded Deer", by John Trout.

Education. It's a skill.Also use a trail maker of some kind and get low andlookbackon the makedtrail to get a good picture ofthe linethe deer is traveling.

I have a friend that is color blind and cannot see blood on the ground, so he invested in a thing called BOWBUG..... But if you can see just fine, I would do it the old fashioned way!!!

Yep! A priceless tool! Especially if you are without it!