First things first. Whenever you want to play video games, it's best your not using WiFi. WiFi causes lag. Especially in a
country like yours, so far from the server. Always be connected using an Ethernet cable. No lag, and always connected.
Secondly. If your not familiar with any game settings, try using the Console to put this Command in :
/cl_maxpackets 100 - sends the maximum amount of packets to the server to obtain a solid connection
To access the Console - go to Options - Game Options - Enable Console - Yes - then press the key just below ESC
you should see a bar at the top on the screen - thats the Console - type in that Command, press Enter then press the Console
key again to remove it.
Let me know if this helps