ok for the first shot, take a picture of that table filling the frame with white. Then (with the mode dial set to Av) hit "menu" and go to custom white balance set the table image as the custom WB shots. Then hit the white balance arrow on the back (I don't remember which one since I got the 20D now) and change it from auto to custom then shoot. This tells the camera that that table is supposed to be white and to alter the color tone a tad for better accuracy. Now, in aperture priority mode (Av) turn the quick control dial atop the camera until the rear mini status LCD reads 8.0. Change the angle on the bowl of shells a tad, crop closer and put it a bit off center, that should vastly help the shot. The custom white balance will kill the orange tone, and the F/8.0 will increase depth of field so the shells aren't blurry.
For pic 2, again, set custom white balance, that orange cast is horrible, avoid auto modes as much as you can (use P, Tv, Av, or M for ALL of your shots) zoom in more on the rings of light or possibly take this shot in a dark room altogether (meter off of the LED's reflected light, meaning, turn off all the lights, point the LED at a white wall, aim the camera at this wall, press the shutter halfway and keep it held down, then have the girl start spinning them and fully release the shutter)
pic 3, the hwitebalance is an example of what you should go for in the future but.......... the lemons are a bit boring, also, flash seems to have been used and lighting caused by built in flash is quite harsh and boring a red piece of semi-transparent plastic over the flash might have made this shot cooler.
shot 4 seems a bit boring and can do wihtout the lens cap. Remove the cap, get a lower angle(like seeing the plate kind of from the side but still from the top) and (using the rule of thirds) get the plate in the bottom left or right corner cropped off a bit so that its center is in the intersecting lines of the rule of thirds (if you don't know what that is, draw an imaginary horizontal line 1/3 from the top of the frame, another 1/3 from the bottom, a verticle one 1/3 from the left and 1/3rd from the right, the intersections of these lines generally pose a more interesting location for subject composition, some shots work better defying this rule but it works more than it doesn't)