So your shirt and tie don't have to match your suit.. for example you buy a Navy Suit. don't go looking for a blue tie the same colour! unless you want to look like a waiter who's black suit was at the cleaners!
Your shirt an tie should be a winning combination that complement a suit. For example, if you were to buy a Navy Blue suit, you can wear. a purple shirt that compliments the suit with a tie made for that same combination. You can alway marry the whole look together with a pocket square.... if your not sure what a pockets square is.. look at the picture below.. (hint.. its in the pocket) there are many colour combinations you can put with different coloured suits. Except one.. Dark navy ties do no go with Black Suits... PERIOD!