Huygens' wave theory The wave theory says that every point on the wavefront is taken as a source of secondary spherical wavelets. Now what I want to know is
what does this actually mean?
As every point is producing waves will they not interfere with one another? Will we be seeing an interference pattern?
I am just unable to visualize it in my mind.
Can somebody please explain it to me what the theory is all about? And do it in a simple way so that I could visualize it better.
 A: Basically Huygens Principle is just a way that was envisioned in the 17th century to describe how wave behaves and is understood as in the following picture. 
Each point on the wavefront radiates spherical waves which interfere to preserve it during propagation. 

This picture is inspired from Rayleigh Scattering where the emitters are actually all the electrons of the atoms in a material which react to the electric field. 
Though Huygens principle is not completely correct, in particular one needs to add an obliquity factor to prevent backward propagation.
Moreover for large wavelength on small aperture the Huygens principle is definitely no longer valid. 
To sum up I would say that Huygens principle is a convenient way to describe wave propagation and particularly diffraction which happens to be adequate in many cases. However this principle is not fundamentally right.
A: I don't know the idea in detail, but broadly speaking you take some points on the your wave, draw spherical wave maxima around the points, and then find where there is constructive interference. This will give you a set of new points that basically describe where the wave front ends up.  
Of course, in nature this is supposed to happen for each of the infinite number of points on the original wave, and not just a few, but that is not possible to visualise.
A: Huygen's principle is that each point of a wavefront is the point source of secondary waveform.
Another point is,all secondary wavelets spread around in all directions with the speed of light.
Another is,if we draw a common tangent from all the spheres, we will get the resultant wavefront.
