To improve your altmetric scores you need to create an online presence and share information about your work and your research outputs online.
There are many ways to do this:
Blog about your articles or work, and ask others to write blog posts about your work.
Become active on Twitter and tweet links to your articles and other work.
Create a profile and add your publication list to social networking sites for researchers, such as Academia.edu, ResearchGate and Mendeley.
Make all your research outputs, including data, code, videos and presentations, available online by using on content hosting tools such as figshare, Dryad, YouTube, Vimeo, SlideShare, SourceForge or GitHub.
Deposit your work in the University of Melbourne institutional repository Minerva Access, or a subject-specific repository such as arXiv (a repository for physics and mathematics).