I am Sabahat Ali, working as an SEO strategist on one of the E-Commerce companies in Pakistan. I have been helping newbie e-business starters with the respect to SEO for the past 1 year.
The preliminary thing you gotta do is to conduct keyword comprehensively.
Once you are done with it, you need to decide which keywords to target your home page. I'd suggest ONE PRIMARY KEYWORD and two secondary keyphrases attached with that primary keyword.
Home page can be well targeted by incorporating keywords in Title, description, h1 and h2 tags... You need to make your content keyword rich, for this you may need to add and edit your current content.
Then off-optimization starts with link building. Some of the methods that I suggest are:
i) Press Release Syndication System (Submission of PRs in handful of 25 Press Release Sites which allow ANCHOR TEXT and they are further syndicated into hundreds of other News sites resulting in 1000s of backlinks in a month with only few press submissions)
ii) Putting up links in search engine indexable community, forum and social network profiles with keyword as your anchor text.
iii) Commenting on Do-Follow High PR blogs.
iv) Analysing the competitors SEO strategies in terms of linkbuilding and beating them in quality and quantity.
V) Link Wheel Using 15 Top PR6+ Web 2.0 Properties on keywords stuck on page 2-3 of Search engine.
VI) Last but not least, bookmarking and RSS syndicating of every possible Backlink including linkwheel, profile and PR backlinks.
VII) If you are familiar with website branding then you need to introduce a link-bait idea that your target market would love to link. For e.g. any valuable service you are ready to give them in free or a list of informative things that are helpful to them or memorable videos, content or quiz on your site. That would automatically increase backlinks to your site in longer run. This another field of effective SEM (Search Engine Marketing).