What kind of images sell best on microstock agencies? I’m going to give you some examples from my portfolio.

Cityscapes

Tourist Attractions
All that may be interested in Different travel companies can be interested in it. Famous cities like Paris, Rome, Venice, Athens and many others are in high demand.

Venice

Florence, Pisa,

Istanbul

Moscow

Architecture

Business centers made of steel and glass, skyscrapers or just modern buildings

Nature

Beautiful meadows
The perfect stock photo should be bright. For example, green alpine meadows with bright blue skies and white clouds. Many of the wallpapers in Windows are good examples of landscapes which could sell on stock agencies very well.

Objects

The objects can sell better if they are isolated on white.

Office tools:
pens, paper clips, paper, notebooks, phones, keyboards, magnifying glass, pencils and so on

Vegetables and fruits
apples, oranges, coconuts, lettuce, strawberries, lemon. You can also make sets of different vegetables or fruits.

Food & Drink:
wine, glass of water, pizza, pasta and other famous and good looking food

Tools:
wrenches and spanners, measuring tape, kitchen utensils, musical instruments

Flowers:
roses, daisies, dandelions, gerbera, etc

Symbols and concepts:
academic hats, round wall clocks, lamps, gifts, scissors cutting red ribbon, balloons, money, musical symbols, electronics

Sports equipment:
soccer balls, tennis balls, golf balls
Plants:
germinating seeds, young plant in the palms

Textures

Water
Water is a very popular subject in stock photography. Bubbles, sprays, drops, simply pouring water - all these images sell very well.

Fire
Beautiful flames on black background:

Sky
The sky should be blue with white clouds. If you want to take a photo of the sun please be careful. Do not look through the viewfinder of a SLR camera on the sun, it can be dangerous for your eyes.

Grass
Green grass on white background or green lawn just mowed. You can get good grass for this kind of photos in some pet shops.

Other Backgrounds
electronics, cloth or fabric, old paper, brick walls, fallen leaves, frost patterns

Animals

Any animals, but not very banal. Many people have pets, so they often send photos of their cats and dogs. If you have a cat or dog try to take a shot like in advertisements for pet food.

Fractals

There is a fun way to make money from.. almost nothing. You can find a number of programs which generate images basing on mathematical functions. Sometimes it turns out beautifully. One of the most popular programs in this case - Apophysis. Examples of fractals generated with Apophysis:

The following subjects are very popular as well (but I haven’t tried to upload them yet).

People

Smiling young women, businessmen in suits, shaking hands, business meetings, girls with laptops, girls with measure tapes around their slim and beautiful waists, people jumping over the green lawn on a background of blue cloudy sky, happy young couples, happy elderly couples, children. A couple of examples of successful portfolios with people:
http://www.fotolia.com/p/280047?order=nb_downloads
http://www.shutterstock.com/gallery-2700p1.html

Vector

Examples of successful portfolios:
http://www.fotolia.com/p/200456817?order=nb_downloads
http://www.shutterstock.com/gallery-70677p1.html

3D

Successful portfolios:
http://www.fotolia.com/p/180138?order=nb_downloads
http://www.shutterstock.com/gallery-52310p1.html

It also can be important to sell images according different holydays. For example, in October the Christmas hysteria begins, when all stock photo agencies are overburdened with pine trees, Christmas decorations, Santa caps, etc. Since March you will find a lot of hearts and flowers (because of February 14).