I felt the obligation to write this blog post because someone lost troops attacking my beached HQ. Like, attacking a beached HQ is probably one of the most trivial things in Boom Beach.
(Note, this is a joke guide, don't complain, I mean like, you should be able to take out a beached HQ without losses 100% of the time.)
Step 1: Army Composition
Generally use any army composition. Bring along some Gunboat Energy, you'll need them in case you are going to run out of time.
Step 2: Starting the Attack
If you want to, Barrage and Artillery the HQ with whatever Gunboat Energy you have, but remember to save some when using Tanks.
Step 3: Deploying the Troops
Deploy all your Landing Crafts. If you are using Warriors do not use Barrage anymore; they will hurt your Warriors (any other troop is fine)
Artillery is always safe to use, throw it at the center of the HQ to prevent losses.
Step 4: Finishing Touches
If you want to and still have enough Gunboat Energy for it, you can throw a Shock Bomb or Medkit or Smoke Screen once the HQ is down for added effect.