I have a home office and at the moment there's a big demolition going on nearby. Add that noise (imagine house shaking thumps of concrete being pulled up and dropped) to the usual city/harbour sounds and multiple tasks with conflicting priorities and a puppy that wants to play... Sometimes it can be hard to focus!
Here are a couple of ways that I block off those distractions:
Clear your desk
Often I'll get to a point where I have been working on a few different things and I'll have stuff pulled out all over my desk. It's normal, reference material, stationery, snacks, phone.. But when it's time to switch to a new task that needs my full attention, first I stop and pack everything away that it making my desk cluttered. It clears your head and of course gives you space for the stuff you might need to pull out next.
Music playing through noise cancelling earphones
This is one that I first started using working in an open plan corporate office (as long as you can still tell if the phone is ringing!) No more hearing other peoples conversations and outside noise, it's just you and what you're working on. Most people will also see that you are busy and not bother you. Choose the music that works best for you, sometimes I actually go for classical or something without words so I'm not tempted to hum along.
I do this when I really just need to think and write. No other materials needed but my iPad (no other windows open with Facebook or email) and my brain. Sometimes I'll just move to another room where I am not distracted by all the other things on my desk that need doing. As long as it's quiet (or I have my earphones) and I can get nice and comfy and just type.
If you haven't already, give one or two of these a try next time you need to get something done without distractions.