Weel, it's been a while !
The reasons I didn't continue this business are clear :
1) I was too much excited by the method and I did a lot of things wrongly. Indeed, I had 2 calls from my 2 very-first emails I sent so I thought it was easy-money etc. I had to schedule an apointment 10 days later though I had no contract, no sample, no brochure, nothing at all ! I rushed too much and so everything went wrong ! And that's how I lost some clients (missing meetings or mails...

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2) Back from my traineeship, I was then at school (I'm 21) and even if I have some time in the evening, it is definitely not the best time to schedule apointments with potential clients. So I decided to postpone the moment I will do that.
SO, I decided to have everything prepared before contacting new (and old) clients. And as I have a lot of other projects I would really like to develop (and the life on the campus, etc), it's taking more time than what I would like. But hopefully, I will be ready in September and I will be able to contact some businesses again. And this time I'll be ready !
If I had to sum up my journey for now, I would say "Don't put the cart before the horse" .