I went through the album and it easily gave me an idea of your work. There are a few pretty good shots and I agree there are a lot of very average shots. While you've got time on the road you should do some reading on the the basic "rules" of photography. Guidelines really. A quick google search should be fine on the "fundamentals of photography" or the like.
The "rules" you will come across - rule of thirds, isolation of subject, composition basics etc - are made to be broken. They are not meant to be followed religiously for every photo, but they WILL help you take your photography to the next level.
The main issues I had with your images was composition and isolation of the subject. Your 50mm goes all the way up to aperture f/1.8, which will allow you to put the boxer in focus and isolate her from the background. Having everything in focus often distracts from the subject. You should also be aware of where to position the boxer in the frame. If she is looking left, have her positioned on the right third line so that she can "look" into the space in front of her (as mentioned, google 'rule of thirds'). Also be aware of the boxers expression and frame and post process accordingly, which you have done in a couple of shots.
If you want detailed critique, you need to post a few photos here rather than a link to an album. You will get much better critique that way. However, I think I've given you some things to start on.
My favorites by far were #20, #24 and #42, and they happen to line up with a lot of the said 'guidelines'.
Hope that helped a little and best of luck