Comfort. It’s arguably the most important thing you can do to make your riding experience better.
What kind of bike do you ride? Is it upright, aero, or somewhere inbetween? Chances are, you want your bike to be as comfortable and efficient as possible. What do you plan to do with your bike? How flexible are you? These are questions to ask yourself. A couple of key areas to focus on are the places you come in contact with your bike. The handlebars, pedals, and last but certainly not least, your butt ;
Using a good ergonomic grip or gel bar tape is a good start. Pay attention to the angle your wrists are at when using your brake levers on a flat or riser bar. A good rule is to have them at 45deg. This allows you to use the levers without straining your wrists. With a drop bar your levers should be at a flat angle on the hoods. You also want to have a drop bar angle pointing somewhere in between the seat clamp and rear axle.
For most saddles you want the angle to be flat. Some people like to run Brooks saddles a little nose up. Most importantly you want the saddle to support and fit your sit bones. There are devices to sit on which measure the width of your sit bones. Start with the saddle in the midpoint on the rails. This will give you a good starting point when adjusting front/back or reach adjustment.
Whether you use clips or platform pedals, it’s a good idea to wear cycling shoes. These will provide a stiffer platform for you to stand on and will help to eliminate numb feet. They will also help with performance. Just like finding the right shoe, the correct footbed will make for a much more comfortable experience. If you are clipped in, make sure the cleats are adjusted to the correct position on the shoe. Here is a great video about cleat setup.
It’s also best to have a professional bike fitter do these adjustments.
Tire pressure can also affect your comfort on the bike. Try running the tires closer to their lower psi rating for a softer ride. This will require a little more effort from you but will really improve the ride quality.
I hope these tips help you enjoy your bike even more. Getting a professional fitting done will cover these and much more. It will improve your efficiency on the bike and allow you to spend more time in the saddle.