They get too excited with all the different colours, fonts, and effects that they can create, and feel the need to use every single one on their website to maximise its "wow factor".
Unfortunately in the end it has the exact opposite effect, and people who visit their website will feel overwhelmed by the seemingly random, unprofessional design.
It will make the information presented much more difficult to understand, and will discourage users from spending more time on the site.
Ultimately it will create a website which people are unlikely to spend time on, and will also be harder to find as search engines punish websites with inconsistent formatting, and sloppy code.
The solution is to decide on a style early in the design phase of the website, and then apply that single style to the entire design.
Decide on fonts, headings, links, colours, borders, spacing and then format the entire site using this style template.
The easiest way to do this is by using CSS (Cascading Style Sheets) to define the properties of all the important elements of your website.
If the website has a lot of pages then use a single common CSS file that all of the pages link to.
That way you can ensure that all of the CSS information being used is identical across all pages.
Visit a website that you think is really snappy and professional looking.
Chances are they have used very neat and tidy formatting, nothing overly clever of flashy, but just nicely considered colours, fonts, and headings etc.
The old rule of "less is more" is the best way to go about designing a website and all the HTML formatting associated with it.
Ensuring that the content on the site has attractive formatting is always an important aspect to be considered during the process of designing a website.
However you need to make sure that you don't go overboard, and apply so much formatting to the content, to the point where it becomes distracting, or makes the content more difficult to understand.
The formatting of your content can act as a really nice level of polish which will compliment the overall design of the website.
All you need to do is be careful when you're creating your forms, to ensure that you don't focus on it too much.