Wetter is Better
European rustic bread requires very high levels of hydration, anywhere from 60% to 75%. That means for every kilogram of flour you use, try to use almost 3/4ths kilogram of water.
Slow & steady wins the race.
It takes a time to really invoke the best flavors from your grains. The more you slow down the fermentation process, the better your loaf is likely to taste.
The exceptions to this rule are bread with a lot of sugar in them. Sugars are yeast's food. If you increase the fermentation time for dough with lots of sugar in it, you are likely to get something that tastes overly fermented, perhaps like beer.
But almost all the European bread including French bread will benefit if you reduce the amount of yeast in your recipe and increase the time you allow the dough to ferment.
Bake with High Heat
Every baker wants to get the most oven spring. "Oven spring" is the final rise that happens within the first few minutes of baking once the loaf is kept in the oven. Good oven spring can make the difference between mediocre and great bread.
When preheating the oven to bake European bread, turn it up to the maximum temperature of about 300ºC. Once its time to load the proofed loaves in the oven turn down the temperature to 230ºC – 240ºC and immediately load the loaves for baking. The additional temperature during the first few minutes helps compensate for the heat lost while loading the oven and creates a nice, hot environment that will maximize yeast activity.
Bread requires a hot oven to rise completely so ALWAYS preheat your oven before baking.
Steam the Oven
Professional baking ovens have steam injectors. Right after placing the loaves inside, give them a good blast of steam. The steam keeps the outside of the loaves moist and supple so that the bread can spring for as long as possible. Once the outside of the loaf begins to dry out, it hardens, preventing further spring. Then the crust begins to form.