One of the most important things is probably that you don´t have a lot things that could reflect in the trash can. That´s also the reason why the chrome pipes and fixtures look a bit bland. You ´ll have to either build some geometry around the scene, add some well placed white and black cards or put a nice reflection map into your environment, preferrably a spherical studio HDRI. Presonally I´d go with the last approach, the HDRI, at this stage.
Here are a bunch of free ones. They´re not the best because they´re only 2000*1000 pixels. You can probably find free larger ones.
http://free3dnews.blogspot.de/2011/11/f ... packs.html
Later on, if you build the rest of the room, be sure to include a window and some other kind of light source even if they are offscreen.
Give your light sources a slight color tint, depending on what kind of light it is. Unfortunately Blender doesn´t let you chose light color by Kelvin but here´s a good starting point:
http://en.wikipedia.org/wiki/Color_temperature
As for the texture itself:
Does the trash can have cylindrical mapping or is it unwraped?
If it´s not unwraped, unwarp it and render-to-texture an ambient occlusion pass of the trash can.
Use this ambient occlusion pass as a starting point and as a reference to see where a lot of dirt would be. Dirt gathers in corners, edges and creases.
Paint dirt in photoshop with a variety of grunge brushes with slightly alternatating brightnes/hue/transparency.
Save this as diffuse map.
Turn diffuse map into grayscale map.
Save this grayscale map and create several variations of it by adjusting brightness and contrast.
Use these grayscale maps as reflection maps, reflection glossines and a very, very light bump map. Depending on the dirt it reflects more or less than the metal of the can. It also reflects with a different fresnel value, so it might make sense to crate a fresnel map as well.
Give it a fresnel reflection of somewhere between 7 and 20.
Try giving it some anisotropy and parhaps tangent shading.
I noticed that some of your materials are emitting light. The white ceramic material for example. It should not do that. Your lighting needs to take care of that.