Research
Recommended Tools
Research for Merch is probably the most important step and should be the most time-consuming step as well. I will begin by providing you with a few highly recommended free tools which will make the research step simpler and less time-consuming. The best tool for searching for Merch by Amazon t-shirts I have found is through the Merch Informer website (https://merchinformer.com/merch-amazon-listings/).
Type a keyword, phrase, quotation, niche in the search box and select “Search T-Shirts.” This will provide you with ONLY Merch by Amazon t-shirts which include the select keyword(s) you typed in. These are categorized to be in the “Novelty and More” section. Your goal as a Merch creator, therefore, should be to rank highly in the Novelty section.
Whenever you are browsing through other t-shirt designs, I would recommend installing the DS Amazon Quick View extension, available in the Google Chrome Store. This simplifies the job and saves a lot of time by allowing you to see the rankings or BSR (best seller rank) of t-shirt designs (and everything) on Amazon without having to click on every single listing. Only look at the top highlighted number for BSR.
Main Method of Research
My main method for researching for profitable Merch designs revolves around searching for a generic keyword and then narrowing the results with select phrases, quotations, or alterations of the keywords used such that the search results become more specific. After finding a profitable phrase or niche design, I would then judge the competition, check for trademarks, and finally create or hire someone to create a design which trumps all other competition in the given niche.
This process involves using the Merch Informer search bar to search for broad niches and then searching again for a phrase or more specific niche after finding a potentially profitable design with the DS Amazon Quick View extension. You may already understand how this works but keep reading even if you do.
To begin with, you should only be looking at t-shirts with a ~300,000 or less BSR, as a lower number means a higher Amazon ranking and a larger number of daily sales. If you have the DS Amazon Quick View extension installed in the Chrome web browser, this BSR ranking will be shown under every product listing. If you decide to create a t-shirt design improving upon a shirt design with a ranking of ~300,000 or more, there is a high chance it will not sell. I can almost guarantee that you will find little success if you base your shirt designs on unpopular designs which are rarely selling. If you want a higher chance of selling your t-shirt designs, I would suggest to only find t-shirts below the 200,000 BSR. This is only recommended for lower tiers for tiering up, however, as the 300,000 BSR or below saves a lot of time and works almost as well.
After finding a design below the 300,000 BSR, you should type in the title of the t-shirt design into the Merch Informer search box (to form a phrase, quotation, etc.). You should be looking for Amazon to pull up less than ~50 results. This demonstrates that the niche or phrase is not saturated so that you have a chance to make a sale. When you are more advanced and in higher tiers, these criteria still apply but you will be able to compete with more saturated niches as you can upload more designs and will have more experience in general.
With the idea that you should be only looking towards improving upon designs which are below the 300,000 ranking, make sure that there are multiple designs which are selling for the given niche or phrase that you typed. A BSR below 300,000, from my experience, means the shirt is probably selling once or twice every other day. Personally, I look for three-four designs which are at least above the 500,000 ranking, with one-two of them above the 300,000 ranking as stated before. If you want to spend more time on finding a profitable niche, find designs which are at least below the 200,000 BSR with little competition, as mentioned before, and you will be almost guaranteed to make a sale after creating or outsourcing a decent design.