If you struggle to look for your niche, you can always start finding stuff from around your home. After some practice with goods from around the home, I recommend buying small wholesale lots of products that most people use on a daily basis.
What also matters is what you like to do - your hobbies and interest also would play a role in how you can continue this venture.
Here are a few ideas to start with, as well:
* Clothing: accessories, plus sizes, maternity, night wear.
* Kitchen: recipes, knife sets, toasters, microwaves
* Beauty: sunscreen, insect repellent, cosmetic & toiletry bags, men's grooming
* Homewares: towels, sheets, rugs, throws, cushions, vases, mirrors
* Special occasion: wedding supplies, party supplies, mother-of-the bride outfits, bridal shoes, birthday cards
* Garden : lawn mowers, gardening tool sets, composter
Hope that helps! Let me know if you have any questions.