Fortunately for those who are curious about these questions, there is a very simple and practical trick that can increase the WiFi signal with a can of beer, soda or a drink that comes in a similar package. 

To do this, we need only an empty can (plastic), scissors, knife and duct tape. The process is as simple as you can see in the  image.

Just take an empty can, take a Scissor and Cut it in the shape as shown in the above picture. 

Now Place the Can Behind the antenna of your Modem so that it captures the signals and wont let the signals go pass.
This Technique works like a charm and you will feel the difference. After perfoming this trick you will see Strong Signals and also Signals reaching you somwhat even if you are far away from the Modem.
Tip: Tin can function as a kind of antenna dish and is going to do is to direct the signal with more energy to where that bounces, so try to aim the Tin to the place where mostly you Sit with your laptop in  the House so take advantage of the signal at maximum power.