Finding short-circuit across 3.3V power rail and ground rail on PCB
I have a short-circuit between my 3.3V and ground power rail on my assembled PCB.
  How do I find where the short is?


See below.


  Should I start by removing components one-by-one from the board?


No!!! This should not be necessary. See below. 

Summary: Voltage drop along track sections will lead you to a fault. It helps if I_fault is >> I_no-fault. 

Detail:

A very useful "trick" is to use a voltmeter set to the most sensitive range available (and sometimes a very low current range may serve the same purpose) to determine where current is flowing by measuring voltage drop along tracks. 

Imagine a track A-B-C-D with V+ applied at A and various components and other tracks comnnected to it. Imagine that the short is on a sub circuit connecting to ABCD at point C.
The sub circuit is C-E-F-G with short circuit at point F.

Measuring voltage on ABCD from A to D gives a voltage drop due to current flow along the track.  With the fault current leaving at C, V_A-B and V_B-C will be similar and positive.  BUT V_C-D will be much smaller as the fault current will not be in the C-D section.

In this case the direction of current flow is clear, but if a random section of track X-Y is tested, if V_X-Y is positive then current is flowing from X to Y and if V_X-Y is negative current is flowing from Y to X.

In this case the short circuit has been localised to sub circuit CEFG.
As above V_C-E and V_E-F will be similar but V_F-G will be much smaller as fault current is not flowing in FG. 

If the fault is to ground, as it is in this case, the measuring from various points to ground will give decreasing voltages as the fault is approached physically. 

Once the general method is understood logical extensions can easily be derived.