You need to wear solid colours and avoid printed shirts. Solid colors are timeless but prints can go out of fashion and even be scorned at after a few years.
Avoid graphic t-shirts, patterned ties and plaid shorts as they can go out of fashion very quickly. Even when it comes to colors, darker colors are safer as compared to bright shades.
Basic and conservative colours are highly recommended if you are looking for clothes you can wear years from now. Pink dress shirts are very common these days but a few years down the road they can become laughable, so instead of wasting your money on a shirt that you can no longer wear outside, it is better to pick white, gray, black, tan and blue shirts.
Even if everyone is trying to revive bell-bottom pants, you need to stick to the straight variety, which will never go out of fashion.
When it comes to fittings, don't go for too loose or too tight, both can be outdated. Regular fitting according to your body is recommended, and will not look odd even a few years down the road.
Men should not wear accessories. Things like hats, ties, scarves, jewellery and pocket chains need to be avoided, as these can certainly date a look.
You need to remember that plain shirts, ties, and pants never go out of fashion, so it is recommended that you keep these in your closet. While baggy jeans and pants are in today, but in a few years they will be a thing of the past, just like loose shirts from the 90s.