What we do: Debt collection for companies with international sales.
Our customer: decision makers in companies with international sales and with a turnover under 200 000 000 Euro.
Challenges: One challenge we have met is to actually find the companies with international sales.
We already have customers from SEO, AdWords and adword retargeting and want to know what marketing channel can make 100% more customers in 3 month?
I'll give you some generalized advice from what you've provided but first I need to explain some of the reasons why this is tough for anyone to answer...
First, without knowing how many customers you already have it's tough to strategize a 100% increase. If you have 1 customer, it's different than 100,000.
Second, we need to know how long it took you to acquire the customers you have. A 100% increase could be substantial and if it took you 5 years to get 50,000 clients,
it's unlikely that you'll get another 50,000 in 3 months.
Third, without knowing what you are spending on SEO, Adwords and remarketing and subsequently what you're able to spend additionally, it's difficult to advise you. For instance, if you have a $1,000/mo ad budget I might advise one thing, whereas if you have millions of dollars to spend, I might advise something else.
Fourth, and finally, for now, without knowing your current and target CPA (Cost Per Acquisition), it's difficult to advise you on what new strategies or tactics to introduce.
All that said, I'd start by running a test remarketing campaign across every social channel that allows it. This will mirror your adwords retargeting efforts by re-engaging people who are you've already had an interaction with. IT should make your SEO and PPC efforts more effective.
Next, I'd make sure you truly understand the reasons why your current clients chose you and ensure that your marketing message reflects those attributes.
After that, I'd create some awareness advertising campaigns on social media, with the client-informed marketing positioning, targeted toward a lookalike audience of your current customers. Upload an email list of current customers and create a lookalike audience. Show them videos introducing yourself and then run a remarketing campaign to video viewers.
Finally, a highly targeted direct outreach campaign on Linkedin featuring case studies of the value you bring to your existing clients is never a bad way to work on bringing in new sales.
Let me know if you'd like to discuss this further on Clarity.