If it's simply glare control you're looking for - an interior screen will do the job adequately. However, if heat is a problem, the only effective solution is to mount a screen on the outside of the glass. 
This is due to the 'Greenhouse Effect'. When sunlight penetrates through glass (your window) and comes into contact with anything (furniture, floor, drapes, etc.) the light energy is transformed into heat energy which is not readily able to pass back throught the glass. In effect - the heat is trapped inside. The more windows you have - the hotter it becomes. This is why it's so important to stop the sunlight from penetrating the glass in the first place.
HABITAT SCREENS from Talius
For a superior job of blocking heat and UV rays, consider a Habitat Screen from Talius.
Habitat screens are mounted on the outside of the glass, and run up and down in tracks mounted on either side of the window. When the screen is up, it is stored neatly inside a panelbox at the top of the window.Edge Retention System
One of the advantages of the Talius screens is it's unique 'edge retention' system 
which keeps the screen material firmly in the side rails even in very gusty wind. This same edge retention system makes the habitat screens perfect for insect control on patios as well.
In addition, exterior screens create privacy when being viewed from the outside during the day.The screen material is available in different densities, depending on how much heat/UV you want to block vs. how much of a view you wish to keep. The thermoscreen fabric comes in many different colours to suit your decor, keeping in mind that dark colours work best for exterior applications as well as give you the best view to the outside.
The rails and panelboxes are available in 4 standard colours, white, lt. beige, brown and grey or can be custom coloured to match your trim exactly; and are available in sizes up to 19'6" wide and 12' high.
The screens can be rolled up and down manually from either inside or outside or - can be motorized and operated via switch or remote. For even greater ease they can be automated to go up and down with the sunlight!
DURASHADE D7600 from Durasol
This screen system from Durasol is also mounted on the outside of your windows. Unlike the Talius system, this screen has the option of 3 different guide styles; rod, cable or track.
It can be mounted either from the ceiling, wall or inside the window frame and it simply rolls up onto a roller, similar to a blind. For windy siutuations, it has a special locking front bar that permits the unit to withstand moderate wind.
The D7600 is available in an open weave fabric with a choice of multiple densities or a solid acrylic fabric. The frame components are available in white, sand, brown and ivory and has width ranges from 3' to 20' and heights from 2' to 16'. It can be operated either manually or it can be motorized for your convenience.
