Many sources are available on the web. Knowing how to evaluate a site can help you decide if you want to trust it and believe the information presented. Just because a site looks professional, does not mean that the information is reliable or relevant to your studies.
Watch out for:
Sites which provide information through blogs or articles but also promote or sell products.
URLs which don't match the content or organisation they claim to relate to.
Content which has not been recently updated: look for dates at the bottom of the page.
Sites which are not created by visible and credible authors or organisations.
Sponsored links which lead you away from useful content or advertising which masquerades as 'articles'.