This one is key! Think Goldilocks and her porridge - you've got to find the one that's just right. Most agree the bottom of the tie should skim the top of your belt when you are stood up. Stick to this rule and hopefully avoid looking like Mr Bean.
There's beauty in the details so as a rule for thumb just avoid a teeny tiny knot. When I was at school the girls and the boys had to wear ties so our past time was "peanutting" each other resulting in a knot the size of a peanut (and impossible to untie!). Anyhoo, schoolhood trauma aside, the size of your knot brings balance and perspective to your look so take time to get this right. If you want to go a bit further I like a windsor knot.....it takes time to learn but looks way more luxurious. Its a lot of tying so make sure you leave plenty of tie to work with.
As any man knows, a decent suit is expensive! Fortunately, there's great options from the high street which are affordable and look sharp too. Irrespective of your funds the easiest way to create a high end look is to invest in your accessories. Adding texture through cotton, patterned or tweed ties looks amazing and adds a bit of interest.
You're choosing a tie not a future wife so don't over think it and live a little. Sometimes a classic look is perfect but other times wearing something bold can be an ice breaker and shows confidence. The chaps I know who wear bow ties are some of the most confident I know!