For both men and women: 
1.I suggest that you wear your maroon blazer with a pair of black pants and a white T-shirt. The top should be a deep V-neck T-shirt.

Blazer                       Long/Short sleeve T-shirt               Pants

Wear black shoes with this color combination.
2. You can combine the maroon blazer with a pair of maroon pants and a white shirt/blouse.

Blazer                        Top                                   Pants

And Wear black shoes with this outfit
3. You can wear dark grey jeans and a black top (sweater/ T-shirt) with the blazer.

Blazer                       Sweater/T-shirt                   Jeans

4. You can style the blazer with a grey top and grey jeans.

Blazer                            Top                                Jeans

For women:
1.It is okay to combine the blazer with a beige top and the black pants.

Blazer                             Top                                  Pants

Looks and Examples:
1.

Blazer                       Long/Short sleeve T-shirt /Top              Pants

Photo: Zara