What was the effect of competition among European powers on empire building in Asia? Basically how does competition affect the building of an...

There are two, somewhat contradictory, effects of
competition on empire building.  Competition between European countries made it somewhat
harder for them to each build an empire, but it also made them want the empires more. 
So competition led to more of a push to create empires but also made it harder for any
one country to make its empire.

Look, for example, at what
happened in India.  France and Britain were, at first, competing for influence in
India.  The conflict between the two countries made it harder for either of them to gain
a foothold in India because they were each trying to destroy the other's
gain.

At the same time, however, competition between the
countries accelerated the pace of empire building.  The two countries each felt they
needed to increase the size of their empires so as not to fall behind the other in the
race for power and prestige.

In this way, competition
between European countries had somewhat contradictory effects on empire building in
Asia.