Hello phungminhtuan! Welcome to Steemit! Hope you'll like the community here. As a start, here are 5 tips that we believe will be helpful to you:

1. Keep your passwords safe: Unlike conventional sites, Steemit has 4 types of passwords. Each offers varying degrees of access to your account, so know where and when to use each of them. Also, make sure to keep them all safe and secure.
2. Get Steem rewards: When writing a post, you'll have the option to choose how to receive your reward: "Default 50%/50%" or "Power Up 100%". As of this moment, choosing Default 50%/50% is the better option. But this can change over time. Check our post to know more.
3. Upvote wisely: When upvoting, wait at least 30 minutes after the post is published to maximize your curation reward. Also, make sure not to upvote too much too fast so as not to drain your voting power.
4. Know your Steem, Steem Dollars and Steem Power: Steem and Steem Dollars are the 2 main currencies here. Convert and power up more Steem into Steem Power so you can have higher values on your upvotes.
5. Have Fun and Enjoy!

For a detailed writeup, check our post Getting Started: 5 Essential Tips for New Users.

Good luck on your Steem journey! Follow us if you like to receive more helpful tips and maximize your Steemit experience.