[Starter] Strategy for Retain Keyword Ranking

[paterman]

Hello, 

I Own an old E-shop..with its own niche market.

Could please reccomend me any strategy for supporting my positions in the Ranks I already have
in specific keywords?

In any strategy I choose
1. Shall I write everytime new arcticles each time?
2. Shall I create always new accounts in order to look different?
3. Shall I follow the same strategy Always or not.

Thank you