Vote somewhere between 10 to 20 times per day to increase your odds of receiving curation rewards. Spread your votes out throughout the day to try to get your voting power up in between votes (the higher the better). Unless you have a high value upvote from having a lot of Steem Power don't waste your votes on your own posts. Trying to vote early on posts from users that generally earn a lot on their posts or vote on posts you find that have a lot of money earned already with a relatively low number of people that have votes on it so far because in those instances it's likely someone paid for upvotes and you could get some of that if you're in line for curation rewards. It's difficult to say on the posts because everyone has different strategies. You can do whatever you please though on Steemit.