First - a good backpack is a start, if you keep purchasing you may need more than one
. At least your camera and
lenses will be within a padded bag. If you live in an area with high humidity I'd also suggest throwing in some of those sachets which absorb moisture. I have a Pro Runner 450 which is great for travelling in Aus - not so good for OS as it weighs nearly 5kg empty.
Second - I always carry a microsoft
lens cloth when out shooting to wipe the
lens with. I've only used the cleaning fluid once and have no idea if it's the same for glasses.
Third - I have the
Tamron 17-50 f2.8 with vibration control which is an excellent
lens. Without the VC it will all depend on your technique if hand holding but should be fine on a
tripod. Only one way to find out if you've wasted your $200 - take some photos both hand held and on a
tripod and see what results are like.
Fourth - No - you can never turn a sows ear into a silk purse. A
raw image will usually look flat straight out of camera and of course good PP will bring out the contrast/colour etc and make an image with good bones look fabulous. If, however, it's oof or badly composed all the PP in the world won't rescue it.