What should be strategy toward chasing lower scores?

Before the second inning starts the team
who have to chase the given score makes
strategy how to get through the required
target.Some strategy succeeds but some don't.
If the score is lesser than expected then
Teams might not make so called strategy.
Team thinks that it's easily achievable
target.If chasing score is more then
play fast and put more runs as game
goes on,on the scoreboard.

In fifth match of ODI series 2006,between South
Africa and Australia;Australia batted first and
scored 434 runs in full 50 overs.From Australia
Ricky Ponting played well and hit 164 runs.
In the answer of 434,South Africa hit 438 runs
with Hershell Gibbs scoring 175 runs.No need to
tell who won(If you really don't know let me
tell you SA won by one wicket).A record of
highest runs in 50 over was made on that day
by Australia but broken by South Africa after
4 and half hour.South Africa must have made
the strategy which I had mentioned earlier.
But..if Australia would have scored around
300 or 350 runs it is not necessary that
once again South Africa would have surely
won.

While chasing 183 runs of India during World
Cup 1983 final West Indies might have made the
strategy that end up the match within 30-40
overs.Before chasing small 183 runs West
Indies must have thought of sure win and lifting
consecutive third World Cup because they had
World class batsman like Clive Lloyd and Vivian
Richards.But...they had committed mistake by
taking 183 runs not seriously and they paid
for it and they lost the Prudential Cup to
the Team India which was said beginner at that
time.

So while chasing lesser score on strategy
could be Team might act in real time means
they should take action according to current
scenario of the game and the best strategy
would be 'Don't take any opponent lightly.
Please suggest your strategy for chasing
lower scores if you would have Captain of
chasing Team.