1. Invent products that are physically small. The primary advantage of physically small products is their ease of storage and handling, which makes them relatively inexpensive to keep in inventory. My first inventory of 5000 items was kept at home in our hall closet! Keep in mind, also, that it's much easier to carry a small product to a potential buyer for a demonstration. People always want to see the actual product; not just a catalog sheet or video. I am never without a few samples of my inventions in my coat pocket or my briefcase. I recall making a substantial product sale at 30,000 feet to the guy sitting next to me on a business flight to the East Coast.
2. Develop Products that Offer Repeat Sales. If your product won't wear out, go out of date, get used up, or spoil after your customer buys it, you may never hear from him again. This is why you should try to invent something that will need to be replaced. If possible, try to deal in consumable or disposable products. One of my million dollar ideas was a transparent calendar for the crystal of a watch. I learned that nothing goes out of date with more reliability than a calendar! One corporate buyer set his computer so that every year it issued me a re-order for 100,000 sets of these calendars for use in his Christmas mailings. His orders kept coming for more than a decade!
3. Keep Your Initial Cash Investment Small. Invent products that you can afford to develop by yourself. Stay away from partners and venture capital firms. Beware of those expensive marketing scams that advertise on the radio and television. Keep in mind that it is common for new products to fail. Unless you have a sizable cash surplus, it's prudent to start out playing with small chips. Don't mortgage the farm! Work off your kitchen table and keep costs down. By being conservative in this way, if your new product fails, the financial hit will not wipe you out. And, you will have left the way open to try another invention later.
4. Have others do your manufacturing. Too many novice inventors rush out to purchase machinery so they can go into production. Usually the equipment they want is quite costly in terms of initial outlay, operation, overhead and maintenance. Avoid this approach in the beginning, because there is a much cheaper way to go. The best solution to getting your invention manufactured is to sub-contract (or outsource) the work to a qualified vendor. No mater what you invent, there is a company somewhere that can produce it for you. You keep you risk low, by not putting cash into machinery that you may not need all the time. You can find dozens of companies that can make your product. Let one of them do your manufacturing, so you can concentrate on the more important job of marketing it..