1. Never match.
Never ever, I mean never wear a matching Tie and pocket square. The folks at Moore's in Canada or Men's Warehouse in the US may try to tell you that your Tie and Pocket Square should match but that is the first step to looking like every other shlub in a cravat. Your tie and pocket square should play off each other but never match. You can use one of the colours from the tie or you can try to stay within the same colour family to achieve the desired look.
2. Make a solid choice.
When picking out a combination make sure that at least one component is a solid colour. The tie tie and pocket square could be loud but keep it in line with a solid shirt. The shirt and pocket square could be loud like above but comeback to earth by using a solid tie.
3. Say no to silk, unless it's knitted.
There is nothing worse than your dads shiny silk tie. Try to use different textures and fabrics to build interest in your look. Swap out all those solid colour silk ties with a silk knit. I guarantee you'll receive lots of compliments. Change out your silk for wool and heavier fabrics in the Fall and Winter and use Cotton and Linen in the warmer months to add depth to your outfit.
4. Don't be afraid to mix patterns.
There is one cardinal rule when mixing patterns. That is, to make sure your scales differ. If your tie has a large pattern make sure your shirt has a smaller one. If your shirt has the large pattern make sure your tie is either smaller or a solid colour. The key is to try things, if it doesn't look right to you then it probably isn't right. Feel free to check out my Instagram feed for some ideas.
5. Have fun.
If you follow these rules and find colours that go well together like Blue and Brown, Grey and Blue, Purple and Silver you should come up with some great combinations. See below for some more ideas.