Summarize:

A velvet blazer is a timeless look that you can wear well after the velvet-revival trend has passed.  Some cuts and colors will be more versatile than others, though.  Jewel tones like deep reds and blues look gorgeous in velvet and carry the added bonus of transitioning seamlessly from day to night. A form-fitting, structured blazer is most versatile as far as cut goes, while a cropped velvet bomber jacket can be rocked recreationally. Vintage and thrift stores are great places to look for velvet blazers, or you can check out modern retailers Though your velvet blazer is undoubtedly a versatile piece, your go-to velvet jacket can’t go with just anything.  Since it has such a conspicuous texture, you need to pair it with subtler textures which will offset the velvet rather than competing with it. Cotton, wool, and cashmere are good, neutral-texture options, while shiny silk, tweed, or lace should be avoided. In order to make your velvet blazer look chic but still casual, you should wear something casual or understated underneath.  A neutral camisole or tank top are always solid options for work or play, while a funky band t-shirt can add an edge to the classy, velvet vibe. Stripes are also a great way to make a look more casual without being boring.  A striped sweater, tee, blouse, or tank top beneath a velvet blazer adds an interesting, sporty twist to an otherwise formal look. A velvet blazer can go with practically anything, including formal trousers, dresses, skirts, and jeans.  In order to make it casual, though, you’ll want to pair it with some jeans.  Distressed and light colored jeans are in style, so feel free to experiment with these trendy looks.  When in doubt, though, go for a solid, dark-rinse that looks appropriate in a variety of places and milieus. Boot-cut, skinny, and straight leg jeans will pair well with any blazer.  Flared jeans are also making a comeback, but be aware that a dramatic flare under your velvet blazer might make your look overly vintage or costumey. Depending on your personal preference, you can top off your look with a variety of footwear.  Flat combat boots or knee-highs will create a particularly laid-back feel to your ensemble, while wedges or heeled booties will add some height and polish to your look while still keeping it low-key. Platforms are back in fashion and can play up to the vintage feel of your velvet blazer without seeming overly retro or antiquated.
Choose the right jacket. Look for fabrics with different, subtle textures. Wear a casual tank top or sweater under the blazer. Slip on a pair of dark-rinse jeans. Wear flat boots, wedges, or chunky-heeled booties.