it's not a secret actually ,If you browse the forum regularly you can surely find some ways to earn Bitcoin.Your earning amount depends on your skills,If you have some skills like trading, programming, development etc then you will be able to earn more than 0.1 BTC per week.Again, Without investment you can earn up to 0.1 BTC per week by joining a signature campaign.
Even earning from signature campaign needs some knowledge about something like mining, economy, trading etc. However earning from signature campaign is much less than the other options as trading or offering skills, totally depends on the ability, skills and knowledge of the user. A good designer or developer earns far more than the usual content related freelancer (on an average) so make sure that we are giving priorities to the right things & options.
Yeah , the single way of earning cannot be the secret of earning .01btc per week .
You need to understand all the logic happening in the bitcoin network to make your mind most attentive in every field of bitcoin .
With this knowledge you need to get all the basic need of the price ideas of the altcoins which results into the big earning during the travele as bitcoiner in the all ways of earning .
So making and doing work in every filed will surely results into the earning of more than 0.1+ btc in the week .
I have seen some people who have very less knowledge about bitcoin and cryptocurrencies overall but they are really interested in the future of this technology so they don't waste their time in looking for free bitcoins because they know that the investing their time in a wise manner would give them higher returns and thus they earn in fiat currency and purchase bitcoin with that earned money.