Marketing options for sole practitioner accounting practice

The background is posted here.

A recent analysis of my business new client acquisition showed four things:
1) Virtually all new clients self-selected me after reading published online reviews.
2) By the time I became aware of them, usually by their telephone voice message and my returned phone call, there was no further sales process. They were either already convinced to hire me or else a client relationship did not happen.
3) This does not happen often enough to provide me with a full time income.
4) All other efforts at obtaining clients had little or no tangible results.

The next logical consideration was this: Should I focus on expanding what is working or focus on improving what is not working?

In other words, I could focus on increasing the number of endorsements on sites like Google, QuickBooks, LinkedIn, Facebook, local television stations, print media or TaxCure. This would possibly increase the occurrence of what is already working. (Strategy 1 – endorsement)

Alternately, I could focus on improving what is not working. I could encourage the hundred, more or less, people who endorsed me in published writing or video on the past to take additional action to endorse and refer me now and in the future. (Strategy 2 – referral)

Or I could focus on improving the process where a person who expresses interest in a service but declines to become an immediate client is nurtured until they do become a client later. (Strategy 3 – nurture)

Maybe I should give in to those saying that paid Google advertisements work if I am willing to spend $2,000 per month. (Strategy 4 – advertising)

Most recently, a LinkedIn marketing expert said that I should focus on making personal contact in Chamber of Commerce and BNI meetings and then nurture those contacts online. (Strategy 5 – in person).

There is always a possibility that a yet unidentified strategy will emerge. (Strategy 6 – other)

Some people say that you need to do all of the above. Sounds exhausting, inefficient and nearly impossible.