A website can look professional and still fail to generate results, because the difference between a site that converts and one that doesn't usually comes down to mistakes that seem minor but have a direct impact on user experience and business metrics. These are the five we see most often when we audit websites, and how to avoid them.
1. Not having a clear value proposition
This is the most common mistake and also the most expensive, because a visitor lands on your site and in less than 5 seconds needs to understand what you do, who you do it for and why they should choose you, so if your hero section is a generic line like "Innovative solutions for your business" you're losing visitors before they even scroll.
A value proposition is not an advertising slogan but a concrete statement that connects what you offer with your audience's specific problem, so that it answers on its own the question every visitor is asking, which is why they should stay on this page.
To fix it, write your value proposition saying what you do, for whom and what result they get, something along the lines of "We design digital interfaces that help startups turn more users into customers", which is specific and benefit driven.
2. Ignoring the mobile experience
In Argentina more than 70% of web traffic comes from mobile devices, and yet most sites are designed for desktop first and then "adapted" to mobile, so the result is illegible text, buttons that are impossible to tap and forms that frustrate the user.
Mobile-first design means thinking about the experience from the smallest screen and then scaling up rather than the other way around, which forces you to prioritize content, simplify navigation and optimize every interaction for the real context most of your users are in.
To fix it, design for mobile first with a minimum font size of 16px and tap areas of at least 44x44 pixels, and test every critical flow on a real device rather than only in the browser simulator.
3. Not optimizing load speed
Google reports that 53% of mobile visits abandon a page that takes more than 3 seconds to load and that every additional second reduces conversion by between 7% and 20%, so speed ends up being a business variable rather than a technical detail.
The main culprits tend to be uncompressed images, heavy fonts loaded unnecessarily, third-party scripts that block rendering and the absence of lazy loading, and many of those problems originate in the design stage rather than in development.
To fix it, compress every image to WebP format, limit fonts to two families with strictly the weights you need and use lazy loading for the images and videos that sit below the fold. Then measure with Google PageSpeed Insights and aim for a score above 90 on mobile.
4. Weak or nonexistent calls to action
A site without clear CTAs is like a store with no "open" sign, because the user may well be interested but if you don't tell them what to do next they leave, and they don't always come back.
The most common CTA mistakes are using generic text like "Submit" or "Click here", hiding the main button below too much content, failing to visually distinguish the primary action from the secondary one and not repeating the CTA in the page's key sections.
To fix it, give every page a clear goal and a main CTA that reflects it, using specific action verbs along the lines of "Request your quote", "Book a call" or "Download the guide". The button should have high contrast against the background and be visible without excessive scrolling.
5. Not measuring results
Designing a site and not measuring its performance is like launching a product and never talking to a customer, because without data you're making decisions blindly and what you don't measure you can't improve.
More than the absence of analytics tools, the mistake is not defining what to measure, so before designing you should be clear on your KPIs, whether that means conversion rate, time on page, bounce rate, scroll depth or CTA clicks, and each of those metrics should be tied to a concrete business goal.
To fix it, install at least Google Analytics 4 and Google Search Console, define conversion events for every important action and set up a simple dashboard you review each week. The important part comes afterwards, when you use that data to make informed design decisions rather than deciding on intuition.
These mistakes aren't exclusive to amateur sites, because we see them in companies of every size and even in some that invested significant budgets in their digital presence. The good news is that they're all fixable and that the return from solving them usually shows up quickly.
"Simplicity is the ultimate sophistication."
Leonardo da Vinci