Edit: my original answer is below the line, the first part is based on a comment by Hugo.
There is a site for explicitly this purpose, called aptly swapfig.com.
However, I can't verify their reliabilityIt works by connecting other users either via a wanted or an offered ad, as I haven't yet used the site and it's FAQ has failedif the other party accepts the trade you have to loadexchange postal info and send the answersminifigure. When the minifigure is received you have to check a box in the questions which would shed light on their operating principles on two separate daystrade process page and from three different devicesyou can leave a comment. Same if the item is never received. Like Bricklink, building a good reputation is necessary if you want to be trusted in making exchanges.
IfOr if by trading, you mean buying and selling, then there are many suitable websites:
Here you can sell any minifigures you have and use the revenue to buy others, all the while enjoying the benefits (buyer and seller protection, market share, infrastructure) of an established site. Using these sites might not be straightforward for the first time, so be sure to read up on their own rules and customs, or ask around to learn what you must/should/could (not) do on them.
If, however, you mean "trading" rather as swapping, without involving money, then you might truly be out of your luck, asmindful that there can be huge differences in the value of a minifigure. Depending on age, condition, accessories, rarity and of course desirability, there can be a price range from under a dollar to hundredshundreds of dollars for a single minifigure - so one-for-one trading is not really viable.