Search engines are looking for meaningful contents. The search engines will view niched sites as the experts and rank the niched sites higher.
Many websites will have multiple unrelated topics. By organizing the topics into their own silo, the search engine will see clearly the website is focusing on those niches and and view the websites as the expert of those niches.
By building up your silo structure in your website, you are building a strong internal links for the niches. The well structured internal links will signal you are the expert of the niches.
Silo Structure is a SEO silo strategy to maximize the effectiveness of your contents. By having a SEO silo strategy, you will organize your website better. By organizing your website better, your visitors can find the topics faster and deeper. The search engines will think you are the expert of the niche because there are rich amount of related articles and the related articles are easily be found.
Silo structure is to organize your articles into separate categories. Each category has its own subcategory. The articles in the subcategory will link to the higher category and vise versa. This way the related articles will be tightly linked.
You do not want to link to articles outside of your silo because this will confuse the search engines the topic your articles related to. This is not a strict rule to follow but try to minimize the internal links to unrelated articles in a different silo.
You will need to understand the niches you will choose for your website. You will need to understand the topics are going to be in your niches. Try to wrtie a list of topics that comes into mind. You can find some ideas from the categories in your competitors' websites in the same niche.
Now you have a list of topics. You will have to organize them in a logical hierarchy. This way the readers can search the subtopics quickly. You will also need to make sure the topics are not duplicated in your website. Sometimes a subtopic can exist in two categories. You will have to decide which category will be the best represent the subtopic in your website.
Now you will research potential keywords for each subcategories. You will use these keywords to create articles for each subcategories. To avoid cannibalization, you will need to make sure you are not using one keyword in multiple articles. Having a silo structure will help you avoid cannibalization.
To connect each articles, you will set the internal links to connect the categories and theirs subcategories. The internal links will signal the relationships between articles to the search engines. When the search engines see the linked articles are in the same topic, the articles will have higher authority to the search engines.
Here is an example building a silo structure in SEOSiloing.com
Here is an mindmap example using SEOSiloing.com Mindmap.