1: your white balance is completely off in most of the pictures.
you are lacking a lot of color and warmth in most of those pictures.
look up white balance adjusting on your camera, i usually do custom white balance (keep a plain white piece of printer paper in your pocket. unfold it and lay it out. take an out of focus picture of just the paper, nothing else in the frame at all, and use that picture as your white balance setting pic. white balance will be perfect in every shot for that particular area/room)
2: composition is indeed elementary. i see what it is you are trying to take a picture of, but i believe you missed the photograph you were trying to achieve. like stated above, rule of 3's.
another example is the pool balls. could have been a good shot (pun intended) but, the cue ball is way too out of focus, and you have too much bokeh (blurriness of the background) which yields a colorful blob in the background.
set that picture up again one night. take care to look at your options of what will be in the background depending on which end of the table you use, use your white balance paper, choose a clean or properly scarred cue ball, and adjust your f-stop to make the balls in the background just blurry enough to make out and snap it again. play around with a couple different aperture's and shutter speeds and see which you like the best.
i believe that there is a difference between photography and picture taking.
photography is art.
picture taking is just taking a picture.
3: all of your pictures seem a little soft to me. mainly the close up shots you took. except the wasp or whatever, that one is pretty crisp.
usually what i try to do is use only the center focus point setting on the camera, point that directly at the item/area that i want in perfect focus, then move the camera to the composition that i want.
also, this is where a great lens will make a difference. you could have a top of the line camera, but a cheap piece of glass will kill the pictures.
also, if you have any filters on the lens, make sure that they are perfectly clean.
dont become a "photographer" that relies mainly on editing to produce a great photograph.
if you learn and practice a lot with aperture, shutter speeds, and iso's you can achieve great photographs straight from the camera.
personally, i love nothing better than showing a photo that i took and being able to say that i didnt edit it.
being able to say "look at what i captured perfectly" is better than saying "look at the editing i did on this one"
main thing i see is the shots of the sol, that red brick, and green vegetation could pop brilliantly with some adjustments on the settings.
one tip i usually give to people starting to learn the manual settings is to use the auto setting as a starting point to shutter speeds etc.
my old xti always makes pictures a tad over blown in auto mode, so i will put it in auto mode, and press the shutter halfway, it will show on the screen the settings its going to use, then i switch to manual and adjust from there.
sorry for all the negative lol. but, its the best way to learn.