Give your bookmark submissions the same consideration and respect you would give a blog post submission, which means being relevant and attempting to add some kind of value to their community. Use multiple platforms, diversify your anchor text, and link only to useful content, not just to your homepage.
There are a few other things that differentiate accounts that can survive versus those that will be either flagged or deindexed:

Use different anchor texts. Mix them up by using the name of your company, partial keyword, and generic “read more here” rather than the same anchor text for all of your submissions.

Submit to different landing pages. and not only the homepage of your site or one blog entry. Diversify your submissions to service pages, blog entries, and resource pages as well to make it look like you are sharing actual content rather than promoting the same page.

Keep track of your submissions in a spreadsheet. It will help you avoid duplicates and understand what platforms refer users to your website.

Check your old accounts from time to time. Activity on your profile is rewarded on the platform itself and search engines appreciate that as well.

Expert Tips

In terms of off page SEO, the accounts that do well over time are those that are taken as actual accounts and not just link farms. It is important to log in now and then and to interact with what other people have submitted on their site, thereby creating a history of activity.

In addition to this, there are some general pieces of advice which can have quite an effect:
Use bookmarking alongside with valuable content. It is very hard to get engaged through a generic page of any product, while something useful like a guide or even an original research paper will certainly attract more people who will actually click on it or give it an upvote, making the link more trustworthy for the search engines.

Look out for platform updates. Sometimes bookmarking platforms become nofollow, change the policy on moderation, or even go out of business. To make sure you are not linking to anything irrelevant, audit your submitted platforms at least once per quarter.

Take care of mobile optimization. Bookmarking platforms are often visited from mobile devices. It may be less likely that people will engage with the resource if it appears cut off from the phone screen or looks unattractive.

Bookmarking is part of a wider picture. The most successful companies use bookmarking together with other off-page marketing channels like guest posting, digital PR, citation, and organic social media.