Hygiene: There is significant evidence that so called "water bore" pests such as giardia are most frequently passed on by poor personal hygiene (e.g. not washing hands during food prep) rather than being direct contact with contaminated water sources. If hands are visibly dirty you should wash your hands to get the particular matter off them. Once large particle matter is removed, Alcohol hand gels are more effective than soap and water washing to clean hands, as well as gentler to the skin. The CDC recommended use of alcohol gels in medical setting rather than the older surgical scrub with water.Take care of your teeth. [FINSHME: Back country "sponge bath"]
Preventing Blisters: It's a lot better to prevent blisters than treat them. If you notice any problems, immediately treat the area. Don't wait to see if a blister will develop. Most "hiking" blisters are caused by friction. There are several techniques which can be effective. The first is to remove the source of the problem. Sometimes the friction is caused by ill-fitting boots, uneven fabric, etc. These things aren't a big deal if you are walking a mile or two, but after 10-20 miles it can be a real problem. So the first step is to do some shake down hikes to make sure you shoes / boots fit, etc. The second technique is to have some sort of cushion that buffer preventing friction against your skin. One of the best ways to do this is using two socks as described in the "socks" section of my clothing recommendations. The third approach is to put a protective layer over the skin to protect it from harm. There are a variety of blister prevention pads such as Spyroflex bandages which function as a second skin. The Forth approach is to reduce the friction by making things slide more easily. One of the most common tricks used on the trail is to cover "hot spots", areas that you can feel "heat up" with duct tape. The duct tape both protections the skin and reduces the friction.
Preventing "Saddle Rash": Next to blisters, the next most common occupational hazard for hiking is "saddle rash": an irritation of the inner thighs or buttock. There are a variety of preventive measures, but the most durable and successful seems to be the use of wicking compression shorts. Another approach is using Body Glide which looks a bit like a stick of deodorant. Finally, some people have found maximizing ventilation by hiking in skirts / kilts is helpful. You can find threads about preventing saddle rash on many forums related to long distant hiking. Treatments for chapped skin can also help prevent problems such as Udder balms such as Udderly Smooth.
Hiking In the Rain: Staying dry is quite challenging if you are engaged in aerobic activities. because you need to not only protect yourself from external moisture, but also have to deal with internally generated moisture (e.g. sweat). The trick, in most conditions, is avoid overheating. There are a number of things that I have found that help reduce internally generated moisture. In order of importance:
The other thing to keep in mind is that getting wet isn't necessarily a bad thing. People often think wet = hypothermia. That is because water is much better at moving thermal energy than air... and hypothermia is about cooling your body's core temperature. In many conditions, it is possible to be somewhat wet and yet still be warm enough. I have found that if I am engaged in aerobic activities, and am wearing something that blocks the wind, that I stay warm enough so long as the temperature is above 45F.
Remember that your body is more or less waterproof and dries very quickly. The problem isn't your body is wet, but the clothing are wet and doesn't dry quickly. As soon as they stop engaging in high output aerobic activities (which can generate something like 7x the amount of heat as sitting quietly) you will chill quickly without added insulation. So the trick is to wear clothing that dries quickly, and have adequate insulation to stay warm when stopping. I used to change into dry clothing after hiking in wet conditions, but I found I don't need to do that. So long as my clothing is not dripping wet (e.g. I have squeezed out the excess water out), my clothing will dry on my body in a warm environment (like my sleeping bag) in 30-60 minutes.
Preserve: We need to take care of our wilderness. If you carry something in, bring it out. Bring an extra trash bag and pack out some of the trash others have left. Consider not having a campfire every night in areas that are low on wood. Leave No Trace
Finish Off: When When I am going to exit in the same car that brought me to the travel head, I will leave a clean set of clothing, comfy wool socks, sandals, some wipes, a towel, comb, and a small container of water. This way I can get clean up a bit, get out of my grubby trail clothing, and enjoy a nice sip of water if I am thirsty.
Other Technique: There are a number of techniques which I have found helpful over the years: