Focused Attention is the ability to give a specific response to a given stimulus.
These processes of consciousness can interact in various ways to enable five different processes of attention: Focused, sustained, selective, alternating and divided attention.
Focused Attention: This can be defined as the ability to give a specific response to a given stimulus.
An example would be if I asked you to cross of all the "s" letters in the line above.
Another example would be if if I asked you to repeat a list of numbers one at a time, for example: "3-8-6-4," "2-8-7-3," "1-6-6-4," etc.
To focus on something, you must be oriented, motivated, aroused and have some innate figure-ground capability.
The next step, of course, will be to hold the focus on a particular figure or task for a period of time, which is called sustained focus.