Hey guys, a very important tip for Boom Beach is to prioritize your Armory upgrades of Barrage and Artillery above anything else. The reason for this is because if you are able to take down key enemy defenses just with Energy then even a weak army will be able to invade the beach and gain you the victory!
It is also important to pay attention to the exact amount of damage your Barrage and Artillery are doing because then you can calculate which towers you can take out with precisely the correct amount of energy. For example, on the below picture you see my Artillery at level 17 is doing 3718 damage, which means I can 1-shoot-kill any 3500 health defensive tower or 2-shot-kill any tower below 7634 health. Then I can more efficiently use my energy and destroy a lot of defenses with it.
The Barrage is more difficult to calculate with because it is shooting a little bit all over the place, so the rule there is basically have as high Barrage as you can so it will also do damage to the surrounding towers and buildings. Still a healthy portion of that damage goes exactly where you click so it matters.
So to conclude, if you ever have a choice to invest in upgrading your army units or other tactics / technologies always pick Barrage and Artillery first. And to make them for effective remember also to upgrade your Gunboat and place Energy statues, at least 1 Masterpiece, but a lot of people go for even more.