The best investment method i think is trading. But you must know about market price before you try it. You can hold your BTC for several weeks or months than you look market price. The other way is altcoin trading. It's faster than BTC trading, but it has high risk, so i don't recommend it. The last thing i want you to know, be careful when you choose trading site or you'll lose your BTC 
i want to add that with great risk comes great rewards. especially now that bitcoin market is stable and boring, altcoin market is a good choice for getting some good profit out of it.of course it is not easy and not for everyone to jump in and start profiting, it is a good way to double or triple your investment in a short time.
How do u like doing that cloudthink.io promotion on your sig/avatar?
I noticed that they are advertising this with full members and above. Have you gotten some btc pay out of this yet? Do they pay you by how many times you post on bitcointalk? I thought about signing up for one of these ad services once I get established.
You might reconsider that campaign. There are strong hints that the project is faked, so to say, its most probably a scam. They used pictures to show their own project since someone found out they took the pictures from another project. And other things. See the following threads:
https://bitcointalk.org/index.php?topic=1076500.0
https://bitcointalk.org/index.php?topic=1074272.0
https://bitcointalk.org/index.php?topic=1076517.0
It is totally a SCAM.. Don't go on their higher payouts and don't get greedy. Just remember "Slow N Steady Wins The Race" So I believe to join some genuine signature campaign no doubt even the pay out is not much higher as compared to cloudthink.io but you are getting paid on weekly basis and thats the best thing;.