While it is not really difficult to get the fundamentals of bike fit such as saddle height, there are few changes that can make a huge difference in terms of comfort and riding speed. Luckily there are some tweaks that can be made in order to get the perfect position.
1) Handlebar angle
Handlebar rotation is normally the first thing that riders think about when it comes to the position on the bike. Where the handlebars are rotated (forward or backward) can make a big difference to how the bike feels underneath the rider. Rotating the hoods forwards will allow a longer reach and an increase in the drop between the saddle height and the hoods. This will grant also more aerodynamic. On the other hand, rotating the bar backwards will result in reducing both the reach and the drop
2) Compact bars
Compacts are relatively recent invention in bike riding. Traditionally, road bike bars had a deep drop and because of that there was such a difference of the position on the hoods versus being on the drops. In order to solve this issue, the compact came up allowing the rider to be in the drops for long rides without getting much of the discomfort
3) Saddle layback
Saddle layback related to how far the saddle is behind the center of the bottom bracket. Traditionally, road bikes had a relatively large layback meaning away behind the bottom bracket. On the other hand, there are time trialists and triathletes who have almost no layback. When dealing with the saddle layback, one would normally change the reach as well. Moving the saddle forward implies the need to raise it
4) Saddle tilt
The international Cycle Union for years banned pro riders from tilting their saddles downwards towards the front as they thought it was performance enhancing and because of that plenty of those pro riders complained of being numbed. Therefore, as for changing the situation one can tilt the nose downwards in order to put more power out in a more aerodynamic position and for relieving more pressure on the perineum to allow a more comfortable ride.
5) Lever reach
This is one of the least commonly adjusted parts of the bike. Most modern design of brake and gear shifters allow to adjust how far the lever is away from the handlebars which can be useful especially to those with small hands.
6) Crank length
When choosing the optimal crank length, one should consider the type of riding, the preferred cadence and the length of the legs.