> I am learning how to read schematics.  
> Are there any rules on reading schematics ?

It's excellent that you ask this question before drawing your own schematics


> It's my understanding that schematics are read left to right, and that is how one should follow the signal, from left to right, is that correct and are there any other rules like this one ?

Left to right, for all the signals that you can, is good practice. All professional schematics follow that. Many amateur ones do. It will grate when you find one of the many that don't, you just have to do more work tfel ot thgir morf gnidaer.

Often however you will get a feedback signal signal that simply has to go right to left. Try to set it apart a little from all the other wires, so you can see what's going on.

Other practices - 

- Use reference designators. When you come to discuss the circuit with others, it's so much easier to say 'R3', than 'the third 10k resistor from the left'.
- Just as signals generally go left to right, voltages generally go vertically, with the DC potential highest at the top. Put the most negative rail at the bottom, most positive at the top, and ground in the middle.
- Ground and power symbols are often used liberally to remove wires to declutter the schematic. Often there are multiple rails, and sometimes multiple grounds, which should be distinguished by different labels on the symbols.
- Never join 4 wires at a dot. Two wires cross without a dot. Four wires join in two, staggered, 'T' junctions. This was a strong rule when we used to copy circuit diagrams physically by dye-line or photo-copying, where printing errors could easily add or remove small dots, turning a wire cross into a 4-way junction or *vice versa*. Most of us still try to follow this rule today and simply make a 4 wire junction 'wrong', but you'll see plenty of diagrams using it. Please don't. Some people and schematic editors use a bridge when one wire hops over another. It may be OK on small drawings, but they don't scale well to large ones like a processor system with memory busses, where they can clutter and even confuse the drawing.

Those are the important ones for me. Others you can find [here](https://electronics.stackexchange.com/questions/28251/rules-and-guidelines-for-drawing-good-schematics).