Head
I make visible the thought patterns and beliefs that hold salespeople back, and help separate them from automatic behaviour — the core of psychological flexibility.
The problem I solve
Good salespeople get stuck. And yet another training won't change that.
Falling results. Training that wears off within weeks. Talented people who leave anyway. The problem is rarely about skills — it's about what lies underneath.
Salespeople who know what to do, but don't manage to do it in practice.
Training that gives a short-term boost, but no lasting improvement in results.
Sales staff dropping out or leaving — with all the recruitment cost and lost client knowledge that brings.
I work on what training doesn't reach: the psychological flexibility behind sustainable sales performance.
20+ yearsof entrepreneurial experience — building and selling companies
ACT · SDT · Ikigaithe scientific foundation of the approach
NIMArecognised instructor/trainer
Previously worked with teams at
Viessmann
Viessmann
The problem beneath the behaviour
Why more sales training isn't always the answer.
In twenty years as an entrepreneur and coach, I keep seeing the same pattern: organisations invest in skills, while the real problem sits one layer deeper.
- 1
Underperformance is rarely about skill. Salespeople often know exactly what to do — but don't get there in practice, held back by doubt, pressure or ingrained patterns.
- 2
Training wears off fast. A few days of training rarely changes behaviour structurally. Without anchoring it in thought patterns, the effect fades within weeks.
- 3
Turnover costs more than salary. Every salesperson who leaves costs recruitment time, onboarding time and lost client relationships — often more than a focused programme would have cost.
- 4
The organisation plays a part too. Targets, culture and leadership style all affect whether people can grow or keep getting stuck.
My approach
Head, Heart, Hands
Sell from Within combines Acceptance and Commitment Therapy (ACT), Self-Determination Theory (SDT) and Ikigai into one practical framework for commercial organisations.
Heart
Intrinsic motivation and values take centre stage, in line with Self-Determination Theory, so drive stays sustainable instead of depending on targets alone.
Hands
I translate insight into concrete behaviour in the sales conversation and the organisation — directly applicable, grounded in Ikigai and practical experience.
Grounded in behavioural science. Tested in the practice of sales organisations. Applicable from the very first session.
Services
Four ways to work together
From one-to-one coaching to an organisation-wide approach — the format follows the question.
One-to-one coaching
Coaching for salespeople and managers who feel stuck in patterns, experience pressure, or want their role to better fit what drives them.
Learn moreTeams & organisations
In-company training and programmes for sales teams and leadership, focused on psychological flexibility as the foundation for results.
Learn moreSales from Within
The book behind Sell from Within — a research-based diagnosis of the mental foundations behind commercial organisations.
View the bookOnline programme (AI)
An AI-supported programme to apply the Sell from Within method independently, at your own pace.
Learn more
About me
Experience from practice. Depth in behaviour.
I combine more than twenty years of entrepreneurial and sales experience with expertise in ACT, coaching and behavioural science. Since 2001 I've built and sold companies myself. That practical experience shapes how I work: theory has to change what people actually do differently on Monday.
Sell from Within grew out of that conviction — looking at commercial results and at the person, the behaviour and the mental flexibility behind it. I focus on the mental health and performance of professionals in commercial and leadership roles.
- NIMA instructor/trainer
- Certified business coach
- MBSR-certified
- Certified in strategic sales management
- Building and selling companies since 2001
Insights
The topics Sell from Within is about
A knowledge library is, to me, part of the long game: not just being found, but being recognised for substance.
Sales psychology
Why sales behaviour is rarely a matter of willingness, but of capability. Thought patterns, stress responses and beliefs shape results at least as much as skill does — and can be trained once you recognise them.
Psychological flexibility
ACT applied to sales: the ability to tolerate discomfort, doubt or rejection without letting it steer behaviour. This is the core reason some salespeople bounce back from a bad week, and others stay stuck.
Sales & organisation
One-to-one coaching works better inside an organisation that supports it. Targets, leadership style and culture all affect whether people can grow — or keep getting stuck in the same patterns.
Recommendations
What people say about me
A selection of recommendations I've received on LinkedIn, translated from the Dutch originals.
"Guido knows his subject and applies that knowledge in a level-headed way. He listens well, asks sharp questions and gets to the point quickly — a reliable sparring partner with depth and calm strength."
Jemuël J. Wilkes MSc
COO, Syncasso
"Guido is a charismatic and empathetic mentor, coach, trainer and advisor who truly listens. Thanks to his guidance, I've been able to get the most out of the coaching."
Ralf Klijzing
Account Manager, Veneta
"Guido is an inexhaustible source of inspiration, combining commerce, psychology and mindful living. With Guido you can spar endlessly — you get straight to the essence, and beyond."
Rick Takens
Area Manager, illycaffè
"Guido has helped and challenged me enormously on habits that had crept in over the years. Open, genuine conversations, with a good balance of calm and flow."
Diederik Nederlof
Founder / Managing Director, Go2Marketstrategy
"Guido is honest, sincere and clear. He motivates with enthusiasm and humour, radiates calm and reliability, and knows when to be decisive enough to confront you."
Erik Van Tetering
Commercial Director, Conservator
The book
Sales from Within
Priority over preference. A research-based diagnosis of the mental foundations behind commercial organisations, built around a four-layer model: from selection and role fit to organisational conditions, psychological flexibility at the core, and the behaviour that follows from it.
I wrote this book — currently published in Dutch — as the first part of a series, and as the foundation for the Sell from Within ecosystem of training, workshops and the online programme.
Interested in the book
Frequently asked questions
Questions about Sell from Within
What is Sell from Within?
Sell from Within is my approach that combines Acceptance and Commitment Therapy (ACT), Self-Determination Theory (SDT) and Ikigai into a practical framework for sales performance. The method works on the mental foundations behind sales behaviour — thought patterns, motivation and concrete behaviour — rather than just conversation technique.
Is Sell from Within the same as a sales training?
No. Sell from Within is explicitly not a sales training agency. Where regular training focuses on scripts and skills, I focus on psychological flexibility and the organisational conditions that cause underperformance and turnover in sales.
Who are Guido Wüner's services for?
For individual salespeople and managers who feel stuck in patterns or under pressure, and for sales teams and organisations that want sustainable improvement in sales performance. This can be through one-to-one coaching, an in-company programme for teams, the book Sales from Within, or the online programme.
What does guidance from Guido Wüner cost?
Every programme — individual or for a team — is tailored to the request and scope. Get in touch via guido@guidowuner.nl for a no-obligation proposal.
Where are you based, and do you work on location?
My office is in Breda, the Netherlands (Druivenstraat 3, 4816 KB). One-to-one coaching and team programmes can take place both at the office and on location at the client's premises.
Ready to strengthen the mental foundations behind your sales results?
Schedule a no-obligation introduction and discover what Sell from Within can mean for your team or organisation.
Schedule an introduction
Contact
What would you like to talk about?
Questions about one-to-one coaching, a programme for your team, the book, or the online programme? I'd love to hear from you.
Email
guido@guidowuner.nl
Phone
+31 6 53412443
Office
Druivenstraat 3
4816 KB Breda, the Netherlands
4816 KB Breda, the Netherlands
LinkedIn
linkedin.com/in/guidowuner