This is the most important resource of clash of clans called gems. There are only 4 ways to get them which 3 are very limited. The first one is to earn them trough achievements which you will complete overtime when you will be playing the game, but after that you will come to the point where you won't have any achievements left to complete.
Another way is to get them trough chopping down the trees and rocks that grow in your village, the trees will regrow with time, but you can only get like one or four per tree which is really limited and won't last you long enough or anything to accomplish something.
If you manage to climb up the leaderboards you can receive a reward for being on of best players, but don't get your hopes up you won't reach it when you are new player because the leaderboards are being occupied by top players that are playing this game everyday for past few years so you don't stand a chance.
The last way is the easiest one and is really simple - just throw your money at the game. Yes if you throw let's say 15 euro you can manage to get enough gems to speed few buildings or one hall upgrade and that's all, but if you don't have the money to do so you are simply screwed up with other options.
There is always the bonus option - you can use our gem generator on our homepage which is free more on that you can read on our homepage.
The game becomes a lot more fun and enjoyable when you have a lot of gems and can use it to speed up buildings and your troops training, but if you don't have them you will be constantly raided by other players which will finally force you to quit the game because of boredom and irritation.