1) Spread the wealth around: When buying an option, make sure you give YOUR SENTIMENT/analysis enough time to take effect! I found that with my first few options picks that my sentiment for the change in stock price was over ambitious. The longer the time to expiration the better chance the option has of being closer to/or in the money! Take one small contract as far out as you can, and move in date wise on your contracts as you gain more confidence in the stock movement! Don't put all of your eggs in one basket.
2) Buying PUTS can be a bit more tricky: One important aspect of buying a PUT option hopefully headed south is that the company may be a candidate for take over or bankruptcy which may actually make the stock price go up! Also, in volatile market conditions, it's hard to gauge the actual health of a company that may have numerous underlying issues and is in constant transition to stay afloat. The management of the company may also be taking extreme measures (not always best practices) to make the company look better than it actually is, so gauging an accurate valuation may be harder to do. I am currently only buying puts on older, slower moving, larger companies that have less volatility. Still can be risky. More motivated buying calls of healthy, focused companies most interested in providing value to shareholders.
3) Liquidity: Make sure there is enough volume and OPEN INTEREST before buying a CALL or PUT option. You can check out your options at BARCHART. Sometimes, if the company is big and the option you are buying is way out there is the future, it is still ok to buy because you may be ahead of the game and will get a lower price than later entrants. Be careful, because you DO NOT want to get to expiration and NOT have a buyer for the contract!
4) The Greeks: Delta, Gamma, Theta, Vega, Rho: Still wrapping my head around the Greeks. The way I see/use this data is that IN GENERAL: Delta/Gamma address the AMOUNT of price change towards expiration, whereas, Theta/Vega address the PASSAGE OF TIME and VOLATILITY towards expiration. Rho has to do with how interest rates effect the option price. Understanding these variables helps me to gauge when I should sell a contract leading up to expiration. Here is an article that discusses the Greeks more.
EXAMPLE: Think of looking through a rifle telescope at a moving target. As the target (Delta/Gamma) is farther away, moving left to right in the scope (the straighter the line better/less volatility!), the image is smaller (risk/reward) and appears to be passing through at a slower pace (time passage/volatility - Theta/Vega) . If the target (Delta/Gamma) is closer (risk/reward), it will appear larger and moving at a faster pace (time passage/volatility - Theta/Vega). This is how I utilize the Greeks. A metaphor for RHO (the fifth major Greek)(variable/fluctuating interest rates) might be how clean the scope is, affecting how well you can zero in on the target!
Good luck out there!