Even though it is perfectly acceptable and is a common practice to use the 8_stage classic model for the e_marketing plan as well, you might want to consider the simplified version proposed by Chaffey, who identifies four major steps to build the e_marketing plan:
Gathering information: this stage is based on the concept of marketing audit. After performing the audit of the macro_environment by analyzing the STEP factors (social, technologic, economic and politic), we should turn the focus upon the immediate extern environment (the micro_environment) and analyze the competitive environment, the costs and the market. Finally, we will conclude with the SWOT analysis, by this way we will have a general view upon the internal environment compared to the external one. The SWOT analysis combine the two perspectives, from the inside and from the outside, because the Strengths and the Weaknesses are internal issues of an organization, while the Opportunities and Threads come from the outside.