Why you should Power Up
First read the following from Steem Blue Paper
Voting with Staked-Tokens to Determine Allocation of Rewards
Steem operates on the basis of one-STEEM, one-vote. Under this model, individuals who have contributed the most to the platform, as measured by their account balance, have the most influence over how contributions are scored. Stake can be bought or earned. Users can not gain additional influence by owning multiple accounts, since one single account with an amount of stake will have the same influence as two different accounts sharing the same amount of stake. The only way for users to increase their influence in the platform is to increase their stake.
Furthermore, Steem only allows members to vote with STEEM when it is committed to a 13 week vesting schedule called Steem Power. Under this model, members have a financial incentive to vote in a way that maximises the long term value of their STEEM.
STEEM that has been committed to a thirteen week vesting schedule is called Steem Power (SP).
Steem Power is the influence token on Steem blockchain. More the Steem Power tokens you hold, more will be your influence. Since Steem Power gives the Steem blockchain long term stability with regards to price it gives the eco system to concentrate on inititiatives which will have long term value addition to the eco system itself. Since the users are vesting their Steem for a persiod of 13 weeks(One quarter) there are compensated in four major ways.
Advantages of owning Steem Power
New tokens are constantly being created on Steem blockchain. This is called inflation. There are certain rules for the rate of inflation which decreases as the time progresses. 15% of the new tokens are awarded to holders of SP. So you can also earn new tokens just by holding SP.
Out of the new tokens that are created 75% of the tokens fund Rewards Pool. Rewards pool is the total pools of rewards that is available to reward the content creators and curators. How the rewards from this reward pool are distributed amongst various content creators is decided based on the upvotes by the overall community. Your influence on this is proportional to the SP you hold. Users with more SP have more influence on the distribution of rewards. In simple terms your vote be valued higher if you hold more SP.
Earn curation rewards - If the content you have upvoted has been upvoted by more number of users have more Steem power then you will earn a curation reward for finding the content and promoting it. The higher Steem Power you have, higher can be your curation rewards.
You will have more bandwidth - Every action that you perform on Steem blockchain like post, comment, upvote, resteem will consume some bandwidth. The bandwidth that is allocated to each users is dependent upon the amount of Steem Power they hold. So the more Steem Power you hold, more bandwidth you will have which means you can perform more interactions on the network without hitting the limits.
You can checkout your Voting Power, Bandwidth remaining and other details on SteemD website. For example if you want to check details of 
Buy in or Work in
There two ways you can increase in on Steem blockchain. Stake can be bought or earned. You can either Buy in or Work In.
WORK IN
You can earn Steem or Steem Power by creating posts that are popular, adding insights to others posts through meaningful comments, by curating good content and so on. This can be hard work especially in the beginning. When you are a new user it can be really difficult to gain recognition as the number of posts being created on the platform is increasing day to day. There are many people who are fighting for attention to their posts.
BUY IN
If you are planning to invest considerable time and resources on creating a brand here on Steem you should definitely consider Buy In option. It will give you the much needed kickstart. Once you have more Steem Power your votes will be valued higer. Generally users tend to leave comments on posts by users who have higher Steem Power as their votes will be valued much higher than the votes by authors with less Steem Power. So in addition to buying Steem Power you should also make sure that you upvote good content including the content and comments by others. Make sure to upovote all the meaningful comments on your posts as it will drive more discussion and more users will start discussing on your posts. This will drive the visibility of your posts much higher.
If you are convinced by now regarding the advantages of holding Steem Power checkout the following sections on how to Power Up. Powering Up is the process of converting your Steem to Steem Power.
How to Power Up
I have used the following two options for powering up. I had used the option 2 when I was pretty new and didn't have accounts on other exchanges. Nowadays I use the first option as I already have some spare bitcoin on exchanges using which I buy Steem. I generally buy steem on Bittrex.
Powering up using the traditional route.
- Based on the country you are from you can purchase Bitcoin from one of the exchanges like Zebpay or CEX.io
- Once you have purchased Bitcoin visit one of the exchanges from the list https://coinmarketcap.com/currencies/steem/#markets. These are the exchanges which have listed Steem. You can click on your favorite exchange and trade your Bitcoin to Steem.
- Transfer Steem from your exchange to Steem account.
- Power Up on Steemit.
- If you use the advanced mode you can also transfer the SteemPower to somebody else.
Powering up using blocktrades
- Make sure that you have a popular currency in one of the exchanges.
- Generate the address on blocktrades.
- Transfer the coins to address and recieve your SteemPower
