One thing that you need to keep in mind when wearing plaid shirts, is that whatever pants you wear, need to be either organic in colour, or generic in nature.
Now this means that you can try wearing browns, khakis, whites and some shades of green, that look more like brown.
You can try and wear black and white, but that would depend on the colour of the shirt that you have on.
Basically, in order to tell if the colour that you are going to wear is decent or not, all you have to do is hold the shirt and the pant next to each other, and then decide if they match.
If they do, then the colour that you have chosen is good to go.
Don’t wear baggy pants
One common problem that people seem to have, is when they are trying to figure out what sort of fitting they need to have on their pants.
Some people try to wear loose pants, but this is a big no. Instead try and wear more traditionally fitted clothes. Slim fitted pants can also do the trick for you if you have the right body type.
Despite you wanting to wear pants, you can always try and wear jeans as well. Or wear pants, that look like they are made of denim, or jeans material.
This will help you mix things up and will look impressive as well.