It has been said that gardeners will share their plants, and share their knowledge, but would never
ever share their compost.
These items (bio-bags and stainless steel compost pail) are on my wish list at
Lee Valley Tools.

The other day when it was warm (unlike now), I emptied the old plastic popcorn -- I mean compost -- bucket and I noticed a ripe odour wafting out of the composter. All through the winter there was no smell, since most of the compost was in kind of a holding pattern. As soon as the sun hits the black plastic container for any length of time, though, the compost starts cooking.
To eliminate the smell I need to add "brown" or "dry" ingredients. Ideally this would be fallen leaves collected in autumn and saved through the winter, but of course I don't have any. [EDIT: We now make a point of saving a bag of leaves.] I have enough junk to store through the winter without actually saving the fallen leaves I collect. So what I usually do is empty some soil from last year's planters into the composter to cover up the ripe "green" or "wet" ingredients and stop them from producing an odour while they cook.
I'm not an expert at composting. What I do works for me. If you click on the title of this post, it will take you to a site on the web that talks in great detail about how to compost.
I only have two tips to share, and the second one might not be available to you. The first is a generally available product called
Compost Accelerator, which is absolutely wonderful and really works to help things along. The other is small kitchen bags made of biodegradable plastic, manufactured by a company called
Bio-Solo. (By small, I mean small enough to line a compost bucket that sits on your kitchen counter.) If these are available in your area, they are worth trying. However, I should caution that I have not yet seen the results of how well they decay. Also, I have read that bags made of cornstarch and soluble oils are better (though they are twice as expensive and each one only lasts a couple of days). [EDIT: I have since learned that these bags are not
biodegradable, but
photo degradable. They need to be exposed to sunlight in order to break down. This means that burying them in a pile of compost inside a dark container is not a good way to use them. Oh well.]

We have two composters in our yard, despite the fact that they are not the most beautiful additions to the landscape. We need two, however, because it really takes two summers to make a rich organic compost. With two composters, we can alternate year-by-year, emptying one and filling the other. Compost at the end of one summer is fine to use; you just have to sift it because it's still a little chunky -- which sounds a lot grosser than it actually is. Some things like corn cobs or pieces of woody stem need two summers to decay properly. If you are going to put these things into your compost, be sure to chop them up as small as you can.
One of our composters is actually disguised from view, come August, by all the plantings around it. The other one is just a necessary part of the landscape. Using black as the colour of a compost bin serves two purposes: it helps the compost cook by attracting the heat of the sun, and black is also the most "invisible" colour if you have to have functional items on display in the yard.
In the lush photo above, taken in August you ought to be able to see both composters. The second one is hidden on the far right (it resides next to the arbour bench) among all the plants. By October, when I have cleared the area to avoid harbouring insect pests over winter, the second composter is clearly on display.

As you can see, there is no real way to hide or disguise the composters, but we don't feel that they are too intrusive. I know other people create lattice or willow-fence enclosures, or use bushes to disguise a composter, but honestly in this case I think that would look more artificial than just having it there on display.
We are proud composters anyway. It's environmentally friendly: we divert about 200 pounds of garbage a year out of landfills -- actually that sounds to me like it could be a low estimate.
And above all composting is garden friendly, and that's nothing to hide!