Avoiding alcohol is easy as long as no one pushes you to drink every five minutes when you obviously want to only drinking water. Drinking culture is extremely annoying.

I'm not sure if you meant to imply the contrary, but club soda isn't the same as tonic water--club soda doesn't have sugar added. So if you're yet to find a replacement for your gin and tonics, you could try out vodka sodas :)

You don't actually drink your decoy drink. You just hold it and maybe sip a tiny bit to make it look like you're drinking so people leave you alone.

A friend of mine adds salt to his glass of wine, to ensure that his decoy drink lasts a very long time.