If employers see a lot of complaining, then they might make negative assumptions about your attitude. Try journaling, talking with a friend, or other creative outlets for airing out frustrations.
There are a variety of ways to upload content, such as photos, portfolios, documents, and links to personal webpages onto sites like LinkedIn. This helps demonstrate your past work experiences.
There is no use in building a professional online presence if you never use it. What might someone assume about you if they see that your LinkedIn has not been touched in a few years?
Have you ever Googled yourself or viewed your social media profiles through the lens of someone else? Is anything on them NSFW (not safe for work)? Be sure to do this with all of your social media accounts.
Privacy settings on sites that you use in more of a personal nature than a professional nature. Keep in mind though that there are ways to obtain access to hidden and deleted content.
LinkedIn allows you to stay in contact with your professional network. It also has job postings that show any connections you have to employees in that company, including alumni who work there. Consider your profile on that site to be an interactive resume.
It might be a good idea to keep most of the content on your Facebook private, as it is a more personal website, but you can share your personality and passion for your field through some of the public parts of your profile, such as any public profile photos and creating a few engaging public posts (you can individually on each post make it public or private).
Instagram is one of the more personal of the social media sites, but for entrepreneurs and artists, it can be a great place to showcase your products and creations.