Welcome Harsh on Ask Digital Vidya. Interesting scenario! Based on my experience, your strategy should answer following key questions:
What are the marketing objectives (e.g. branding, lead generation, reputation management, online sales etc) you would like to fulfill for your client?
Who’s the target audience of your client (segment them based on age, gender, location, interest, behavior etc)?
Based on answers to above questions, identify relevant channels. In addition to Social Media, Search should be definitely considered.
Develop Plan & Process to create (or curate), publish & promote content (including paid media) for the selected channels
Based on the marketing objectives (short, mid and long term), define relevant metrics and identify relevant tools to measure. This should be setup before you go live.
Doing research including competitive analysis would help you strengthen your strategy. Following above approach, do you have any specific questions, which I can answer for you?
On a different note, let me share an interesting approach to target audience for your client through search. For e.g., if you are looking at identifying Indians in Australia, you can target people who are searching for keywords such as Diwali, Sachin Tendulkar, Bollywood related terms as they are likely to be Indians.
Does this help?