Choose a couple of basic color themes and build your wardrobe around them. Wear a favorite skirt, slacks or jacket when shopping for new items so you can solicit sales personnel input on color matching. If you can't tell the difference between two close colors like dark navy and black, avoid buying two identical items in those colors. Or, if you just can't avoid it, mark one with a safety pin on the label. For example, if you mark all of the black items with a pin, then you will know the one without the pin is the navy one.
Shop regularly at the same stores so you can develop a relationship with the sales staff, and they can learn your tastes. If you buy something on advice from a sales clerk and don't get a single compliment on it, take your business elsewhere. Some large stores offer personal shopper service. You phone for an appointment and give them your sizes and color suggestions and describe what you have in mind and they pull items for you to look at and try. They know their stock and can pull together an outfit with all accessories, such as shoes, etc. This is especially helpful for special events like job hunting, a wedding or other important occasion.
Smaller stores are often a good choice because their staffs are used to providing personal service. If your budget doesn't stretch to the higher prices of specialty dress shops or upscale stores with personal shopper service, you can inquire at larger discount-type stores for the best times to shop when they are not as crowded and arrange for someone from customer service to assist you.
Best of all, shop with a friend whose judgment you trust and make a day of it with lunch out. If you offer to pay for gas and treat your friend to lunch, it isn't hard to find someone to shop with. Once a year, you should have a sighted friend evaluate your closet with you to eliminate clothing that has become stained, frayed, or is just no longer at its best. Such items could be put aside for charity or for performing grubby chores. Although you can't see you, others can and it is worthwhile for you to look your best.