HOW TO INCREASE IT ?
Purchase : A permanent solution to your CP requirement. You can buy cards which will increase your CP. ...
Delegation : Another Temporary measure similar to renting with the difference that you don't have to pay the fee.
Since power is simply just the total burn rate of all your cards, you simply need to get more cards to increase your power. Gold foil cards offer 50x the burn value compared to regular ones, which in turn will significantly increase your power.
How do you get DEC in Splinterlands?
This means that players first need to get enough collection power and a high enough rating, before they will be able to earn DEC tokens. Practically this means you will need to win roughly 15 to 20 games to reach the Bronze II League. The more you climb the competitive ladders, the better the DEC rewards become.