Disclaimer
The strategies I list here may not work for some people. They could work for you depending on how fast your swipes are or the game speed. Either way, I hope this guide helps you.
Easy mode
This mode is easy. And when I say easy, I mean laughably easy. Build a good attack force, build a decent size defense, and you should be good.
Here’s a good thing to do that is guaranteed to get you past the easy mode. build a big attack force, as mentioned above, and attack every chance you get. You should be able to crush them in no time.
Normal mode
This is where stuff gets harder. Your enemy will be focused on building a decent attack force, so you should be ready to counter it. Build a good defense. Attack as often as you can. This should get you through the mode.
Here’s a more detailed version of what to do:
Build a decent size attack force. This force should be good enough to beat your enemy at least once. But don’t just focus on attack. Focus on defence to. Build a decent sized defence. You’ll need it.
Hard mode
This is where stuff gets even harder, and this guide gets more detailed. Firstly, don’t bother attacking. Those resources used to build attack troops are better spent on building defense.
Secondly, don’t waste stone. Stone is better used for towers than walls. Don’t bother building walls! They are only useful for your enemies to smash through But don’t actually help you. Build towers instead. They’ll be a big help.
By this point, you should be at the final battle. Make sure you have enough troops to win. As mentioned, towers are a big help and if you have a ton of them, they will guarantee that you win.
Insane mode
This is where stuff gets, well, insane. It is very important that you focus on attack and defense. Both of them are really, really, really important  at this level.  So don’t spend valuable resources on useless things.
Focus on building both attack and defense to about the same size. If you don’t build both of them well, the enemy will notice that one side is weaker than the other. Don’t let that happen.  Build a ton of towers. They will really help you. If you can, build monks two. Monks convert enemy soldiers into your soldiers, which you can use to your advantage if you have a ton of them.  Lastly, don’t go into  fights unprepared. Preparing is very important at this level and one small mistake can result in you dying. I learned that the hard way.
I hope this guide helped you. If you can buy it, definitely give a few minutes of glory a try.  It’s definitely worth three dollars in my opinion.