Hi there, I hope this helps... I've used phases not days. Not much can be achieved or learned in a day, sorry!
Understand, based on your business plan, how much you could pay to acquire a customer. A rough rule of thumb is on third of your retail price, but every business/product is different. This is your cost per acquisition target (CpA). The CpA should take into account the lifetime value of each customer rather than just to profit from the initial purchase. (This is obviously difficult in the early stages).
Try free stuff, like social media. But don't just try in one way. Try different offers and promotions and be clear about what the objective is for each mini campaign. It might be that 'Likes' are a goal initially, just to give credibility. A campaign to do that might look very different to an acquisition campaign.
Only make a decision on whether or not something works if you have enough data.
Try obvious targeted paid for media. The most obvious being AdWords and BING or even paid social. It's best to use somebody that knows what they're doing because the default settings can spend your money pretty quickly and might lead to you discounting something, like PPC, without good cause.
At all times try to collect data. Get contact details, set up retargeting to make your company appear bigger than it is. Start to build a database and learn how to utilise it. Try to ascertain which source of customers/likes/subscribers are worth the most (FB competition entrants tend to be quick to unsubscribe from emails etc. for example).
Make the most of what traction you do get by introducing member get member incentives from day one (if relevant).
Don't ignore traditional media. Just because something can't be tracked with fancy software, it doesn't mean it shouldn't be used or that it can't be a good source of sales.
Make sure you ignore generic advice offered without a good understanding of your particular challenges (like everything i've said above!).
Good luck with it all.