Plan Your Town Layout
There's a solid success rule to limiting damages - WALLS, WALLS, WALLS. You
shouldn't have any weak spots in your village defence. You should have many layers
of walls that attackers will need to get through. You should also place all your
building together in a defendable position, so your cannons and other defences can
protect them all. You want maximum coverage.
Don't Play Defense Only
You should always be on the attack. If you spend your time defending, you're never
going to advance as quickly as if you spend your resources on attacking and
gaining. It's a game, so take a little risk and ATTACK! However, if your shields
are up after an attack, make use of that time - build armies, rebuild your city,
that kind of thing.
Spend Gems Wisely
You get lots of chances to spend your gems on a variety of features. Be careful
what you use them for, because they have real value. Don't waste them on simple
things like getting more time. Use them to advance or get permanent benefits.