First and foremost you should research the Countries you plan on promoting your product in. If you are offering products or services you may need permits, licenses, etc. to conduct business (online or otherwise) within those Countries. Although North America and Australia are fairly open to allowing you to engage their consumer bases there can be some legalities behind it. This isn't advice anyone here can or should consult you on. However I do know within the last three months I've read two articles about small business which were charged $1mil + fines for importing / exporting products on the banned list. One of those Companies sold a box of $0.50/per rubber gaskets to give you an idea of how serious trade legislation is.
Next after you clearly understand if you can legally do what you want; you should actually identify a clear marketing plan. This is your roadmap; if its well written you should actually be able to develop measureable KPIs to track which will tell you if what you are doing is actually working. The marketing plan should go into detail about both online and offline marketing strategies. For online it should cover Copy & Ongoing Copy Generation, Landing Pages, Conversion Pages, SEO, SEM, SMM, SMO, email marketing, viral advertising, and anything else that fits your business and what it has to offer.
If any of this has lost you, you should consult with a professional (and not the type that spams your inbox garaunting that you will get 5000+ twitter followers either), no, a real bonafide professional with a proven track record. They will be able to build a marketing plan for you thats specific to your offerings.
IF however you want to DIY; then all the power to you. After you get your marketing plan in place and you've done some research, come back and ask questions specific to parts of that marketing plan (ie. how do I optimize this website? What are some good practices for Social Media Optimization? What are the current anti-spam laws in the US/Aus? etc.). Then we will be able to give you clear and concise guidance.
Local SEO is one good way to target local audiences. Submit your business, products or websites is local business listings. But make sure your business or products are listed in the right local listings. Make sure the your registered in local listing specifics in your geolocation.
Also make sure that all your listings are accurate and consistent. Put the right and true NAP(name, address and phone number) in all your online listings. Adding you website is also a plus for an effective local SEO.
Well, I would say the first thing that you want to target upon is Localizing yourself ! Make yourself appear over the Google Business listing of Australia and US. Once you get yourself appear over their start talking the help of social media like Facebook, Twitter, Linkedin network create a page and try getting attention of the users over there maybe you could try running some promotional campaigns !!
Try to add as much as possible local business directory listing for your targeted business country. post local classifieds posting for your business. also target your local customers in company's social media profiles.