Shipping Rules Are My Bread & Butter
Today I've just realized that the vast majority of my work has been customizing shipping rules. You'll never be out of work if you specialize in shipping rules. Businesses can never seem to accept the default shipping options and software cannot be designed with a fully configurable shipping rule system. All ecommerce shopping carts try to make the shipping options configurable but they simply can't accommodate all the special needs for pricing and shipping a wide variety of products.
My work experience has shown me many scenarios where shipping rules will probably need to be enforced through custom code. For example, if you are shipping hazardous chemicals you will need to apply extra shipping charges for the special handling. Most ecommerce shopping carts do not provide any options for hazardous products. Food items are another product type that often has complicated shipping rules to apply. A food item may require refrigerated shipping or it may need to be sent on a particular day of the week after certain hours. International shipping often creates headaches as companies can lose a lot of money if they don't charge enough.
Given the vast amount of work to be had in enforcing shipping rules, what can you do to grab some of it? There is actually a lot of preparation you should do. Most shipping carriers offer web services for acquiring shipping rates. You should teach yourself how to use those web services. If you specialize in ASP.NET then you should know how send a request and process the response using ASP.NET. You should request developer or business accounts from USPS, UPS, FreightQuote, FedEx, and any other shipping carrier that offers free access to registered users.
In regards to ASP.NET, there are many specific programming tasks that you'll want to learn. For example, if a product can only be shipped on a particular day of the week then you need to be familiar with the DayOfWeek property for a DateTime object. The TimeSpan object is another important structure to get familiar with. If you have a requirement to ship within 10 business days then you need to exclude weekends from a time span. It can get surprisingly complicated. You might even need to look up US holidays so you don't try to ship on a holiday.
Then you need to study the shipping options and shipping code for many popular ecommerce shopping carts. I have the shipping methods for Storefront extensively documented. I should probably leverage my expertise by studying OsCommerce and a few other shopping carts, restricting myself to their shipping modules.
In addition to all that work there are other considerations. You need to understand UPS zones and be able to desk check shipping charges when a client claims the calculated shipping is way off. It can get very confusing and you'll need to act as a shipping department specialist. :)