Ive just finished a 12 day hike in France, I have done others over the years, some shorter, some longer. These are just MY personal views, other people will differ, in the end I think that over time you will just have to find out whats best for you.
Boots - I've tried them all, all leather, fabric/leather and hiking shoes. Personally I now stick to all leather and boots! My present pair are Brasher Superlights and on my recent walk they were almost perfect, no blisters at all (I buy women's versions, I've narrow ankles) which as a hiker is GREAT! But to make them almost perfect I also use Sorbothane inserts, for me walking on a base boot with only basic shock absorption qualities, after a few days can be just too punishing on the soles of my feet. Why are my present boots only 'almost perfect', I still have to tie my own shoe laces!
Trousers vs. Shorts - Nowadays I always wear trousers. Unfortunately, I know a bloke in our city who contracted Lyme's Disease, he and his family have suffered so much! In the end its a matter of choice or both. One thing, make sure that your trousers are comfortable when walking uphill, I had to throw away a pair because as I hiked upwards, especially in heat, the knee fabric rubbed the skin just above my knees 'red raw'!
Baselayers - i believe in them but do not exactly like them that much, I normally prefer a shirt with a collar, but again I've tried them all. Given a choice now I would only go for synthetics. On a long walk everything needs washing at some point and I hate being Mr. Stinky. My reason for synthetic is that they tend to dry more quickly and personally I think are easier to wash anyway. Some might not agree?
Underwear - For me, needs to wash easily so again synthetic. I have and like Odlo.
Personal Hygeine - Everyone varies. Again, not liking to be Mr. Stinky I have an end of day hygeine routine which I try to rigidly stick to, I like the idea of going to go to bed feeling 'clean and fresh'. I personally carry two of underwear, two baselayers and wash one of each every day. They then dry pinned to the back of my rucksack as I walk. The same with sleeping gear, tights and top, synthetic.
Tent - Mine is one man and I like to be able to sit upright in it. Mine is a Marmot Pulsar 1P and I like it a lot. Its now discontinued but Marmot have come out with a similar model.
My oddities - I don't use a sleeping bag, I use a sleeping quilt and I dont use waterproof trousers, I use a rain skirt.
Rucksac - Mine is a 48L Osprey Exos, the size for me is just right and I think their carry system is excellent.
I could go on and on but I'll stop now!