How to model a spectacle/glasses? from where to start?
Start with a cube. Make it thinner on the Y axis, inset the 2 opposite faces on the Y axis, remove the 2 central faces, fill the hole to have a “quorus” i.e. a square torus. Move the whole on the side, add a mirror modifier, add some edge loops, extrude the central piece in between the eyes and the branch (the part which goes over the ear). Add a subsurf modifer, add some more edge loops and start moving things around…
But first of all: Google Images. You want a model and some (more or less) realistic dimensions. Besides, the model will tell you where to extrude the nose piece, the branch… and all the details you have to think about.
(BTW, I hope you weren’t talking about theater glasses a.k.a binoculars.)
Hi 
Thank you for replying. No your first guess is right. I wanted this - not theatre glasses
Actually I was thinking to model hipster glasses - the modelling looks tricky a bit
It’s not that hard really,glasses are very basic and easy.
Simple plane modeling is the easiest provided you fix the topology afterwards,box modeling is also an option as shown by Kaluura.
How from plane? I will cut the plane or something? 
you are makeing the shape like in 2D fom the front and then you just extrude a bit.
And then you subdivide and add a few loop cuts.
Okay guys, I need to give a try. Thanks for the suggestions. Will let you know what comes up.