Defining advertising mediums to reach clients 
So something happened or certain events are taking place and you have determined that you have a product or service that furfills the need that it generates. How do you go about marketing your products to these people at that moment.
One thing that is important is to determine who your target market is.. Will it be existing clients that you will advertise a new product or service to or will it be new clients that you want to sell your product to? You will definitely use two different marketing strategies for these different groups.
Using a more direct marketing approach for existing customers should perform the best, as they are already familiar with your brand. If you are delivering a good product or service they will be interested in new things that you might offer them. You can make use of email or SMS marketing to drive them to your website to promote these specific products.
To gain new clients you must make sure you are being found when people are searching for you. Future clients might not know your brand but they have a need for what you offer. If you are in their face when they are searching for your product and you make it easy for them to get hold of you, you will reap the rewards. Make sure you have PPC campaigns running on all major search engines for relevant keywords to maximise your exposure.
Make sure that the content on your website is ready to cater for these potential new clients. Setting up focussed landing pages for the specific products will be necessary to make the marketing more relevant.
People will always have certain needs, sometimes in the event of a crisis or certain situations the need increases drastically. If you can see the need and act on it quickly, you will achieve great results.