Better? Yes. 
Best? No. :frown:
Its a big improvement for certain and I managed to get a reasonable result from it...
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...but can you see how your image could be a little different to make it much easier?
Ideally, knowing you will have several of these to do, its makes sense to make things as easy as possible for yourself when in PS...and thus get better results.
You've got the idea of 'contrast' now which makes selection much much easier but....it could be better...here are just some things I would try to do:
1. Keep the lighting constant. Note how your image is lighter on the left.
Whilst not the end of the world selecting a 'narrow' range of a colour is better than a 'wide' range.
2. Avoid shadows.
Again, not the end of the world but avoiding shadows means we don't have to deal with them....and less is more....right? This goes for shadows on the background and also on the object itself...from say a 'flash'.
Lifting the object away from the background not only reduces shadows but also reduces any 'colour cast' created by the background......not too bad in your image but none at all is obviously best.
3. Ratio of object to image.
I did a rough 'outline' of the 'vent' and counted how many pixels it contained.....roughly 218573px.
I then calculated the total amount of pixels in the image...3264 x 2448 = 7990272px
Now, 218573 / 7990272 = 0.027...or just 2.7% !!!
Making the 'object' occupy as much of the image as possible is an absolute must when doing this kind of work.....especially as you have total control over it.
As it stands, 97% of that image we are not interested in.....and that's a lot.
Fill that viewfinder with 'vent' Jennifer......the bigger the better!
These are just what I'd do.....the most difficult there is getting the object away from the background to remove shadows and colour casting but it really depends on how accurate you need to be...the image you supplied is fine although having the object fill more tha 2.7% of the image would be a huge advantage......and this is really easy as you're the one taking the photo's.
There are many varied ways to 'cut out' those pixels now that there is something to work on.....I didn't use a conventional method but they should all yield pretty much the same results.
We're getting there though......its pretty simple to do and if you could take a photo which is more 'vent' than background I'll go through the method I used.....unless someone beats me to it. :biglaff:
Regards.
MrToM.
