Whilst there is no substitute to a professional bike fit (as this takes into muscular limitation and flexibility issues and is done in motion so is the most accurate way to fit the bike) here are some simple pointers. You can do these yourself at home to get your bike set up closer to being correct and more comfortable. This will in turn make you a faster and more efficient cyclist.
Most people who start cycling have their saddle too low which I think stems from the thought that they think they need to be able to touch the floor but this is not the case. At best you may be on tip toes while still on the saddle, it is more important to have the correct knee bend while cycling to prevent injury. As a good starting point I would suggest that you want to set your saddle height so your heel can just touch the pedal spindle with a dead straight leg thus meaning when you place your foot correctly on the pedal then you will have sufficient natural bend at your knee.
Now these are very individual as once you find one that you get on with then I would suggest you stick with it! Its a good idea to demo some saddles first before you commit to buying and you can get a saddle fit from your local bike shop which although may not yield the perfect saddle for you its a good starting point.
The angle can be personal preference based on what you find comfortable, however a good starting point would be level or slightly nose down, what you don’t want is the nose of the saddle pointing up as this can be very uncomfortable for either sex.
Now this is one of the more difficult measurements to get right and basically means how far forward/back the saddle is placed on the rails. Now this is important as too far forward can encourage knee pain and too far back can cause lower back pain/hamstring issues. Basically with your pedal at 3’o’clock you want to drop a plumb line from just below your knee cap and thats where your pedal spindle wants to be.
You want to position your cleat so that the ball of your foot is directly over the pedal spindle, again test this with the pedal in the 3’o’clock position. It is important that when positioning yourself you are also comfortable and can sustain the position.
Now you can change your handle bar reach by changing the stem on your bike. These can vary from as little as 60mm up to 130mm. Ideally if you have purchased the correct sized bike then you should be looking to have a stem around 100mm. However, this can be slightly longer or shorter to make a better fit. Try to bare in mind that if you go too short then this can make the bike twitchy. To see what you require, a simple test is that when you are riding on your hoods then your handlebar should blank out the front wheel spindle (the quick release skewer). If the spindle is in front of the bars then its too short and if its back from the bars is too long.
Your can alter the height of the bike by removing spacers from under the stem. The lower the handlebars are then the more aero you will be. However, this may not be comfortable as will put more strain on your body. This should only be done if flexibility/core strength allows. Ideally a good way to test stem hight and reach is on a turbo trainer. You can make the adjustments to notice how the change feels.
Having a Retul Bike Fit allows a fully adjustable stem to be fitted to your bike thus can be adjusted while you pedal to fully feel the difference between stem length.