I had installed sublime text 3 using instructions for the apt repository stable channel. As the next logical step, I tried installing 'Package control' using 'Tools' > 'Install Package Control'. But even after waiting for 10-15 min there was no response. I have seen the following links. https://stackoverflow.com/questions/38787206/sublime-text-manually-install-package-control
I updated the repository using
sudo apt-get update
sudo apt-get upgrade
Also, I paused syncing with Dropbox. After this I tried again to install package control as in the question above. And voila within a 10 sec a dialog box pops up informing that 'Package control has been successfully installed'.