Each time i sold i lost

[600watt]

i think a lot of us share this experience.

put 90% of your stash in cold storage and do it a way where you cannot access them within 72 hours (when panic mode.)

put 10% on an exchange and play around with a quarter of it when you feel the urge to sell.

[Sonny]

Every time i sold ( trying to rebuy cheaper ) because most of the topics where talking about capitulation, China ban, Russia ban, etc, etc, etc, finished loosing.

Don't listen to those FUDs and don't panic sell your bitcoin
There is no ban in China and Russia.  

[RodeoX]

I have made most of my money in the stock market and on bitcoins by ignoring the common wisdom i highly suggest doing your own homework and deciding for yourself what you think. Also, remember bitcoin was not designed to be an investment vehicle. It should be considered very risky as an investment. try using it as a payment system instead. You may find that for every $100 worth of coins you buy to make purchases on the net, you will be able to spend $110.   
If you are in the U.S., you also owe an additional 20% of any profit you make on bitcoins when you convert back to dollars. Spending is better. Lastly, you should never sell bitcoins at a loss. Hopefully you are only investing what you can afford to loose; that is rule #1 in investing. If that is the case you may want to let it ride. Selling at a loss is locking in those losses. Holding means you still have a chance at profit.