Consider the following:

Colour Temperature—specify the light colour you want
Lighting colour ranges from warm soft light to bright daylight , this is known as colour temperature and is measured in Kelvins.
2700 warm white—normal light for lounges and bedrooms.
4000 neutral white—a whiter light for those with a modern internal design.
6500 daylight— recommended for kitchens, bathrooms, garages and DIY areas.

Wattage / lumen output
Ensure that  you chose the correct wattage to give you the correct lumen output for the function
of the light source. If you find the light too dull then increase the wattage or consider changing
the colour temperature.

Shape
Will it suit and fit into the light fitting?

Have you selected the correct fitting?

E14 Fitting	E27 Fitting	B15 Fitting	B22 Fitting

On each product page it will give more in depth specification and the options available.