Normally my mind is racing with a number of thoughts associated to
closely-related subjects and the ability to harness them and categorize
with little or some degree of emphasis is the most challenging art of
'concentrating'.

It is not that I nor you cannot, but there is something more important,
or more exciting than what you are supposed to be putting all of your
focus into, therefore concentrating on it. The best thing to do is try
and keep all thoughts that have nothing to do with that task or
situation out of your cognitive construct so you can be free of excess
wasted thought. Concentration requires complete dedication and veering
off in any other direction than the one appropriate for the situation,
lends itself to never reaching what or where you wish to go or do.

Cleanse the slate before writing or painting upon it . . . concentration
is unique to its own saturation of required and enjoyed thought
processes brought into action !

*I hope our newest member finds this helpful. please comment or respond.