Getting visible for authors and their books

The hardest part of being an author isn’t writing the novel or even publishing. The hardest part is getting visible. In the not really so distant past authors had to depend on road trips to different bookstores and venues to grab attention. If they were really lucky, someone would land a TV or radio spot. Possibly get reviews from newspapers and magazines.
Those venues are still there and can be successful in reaching readers, but they can also be expensive and possibly limited to local areas...