Using quality ingredients is crucial to baking good bread!
Flour: When choosing flour there is absolutely no need to go for the most expensive brand, but it is essential to choose one labeled "unbleached". Bleached flours contains chemicals that will arm both your health and your bread. Each flour brand gives slightly different results. Try a few different ones to see which suits best your taste. Personally I like to use Trader Joes.
Yeast: I allways use instant dry yeast and not the refrigerated fresh one. It has a long shelf life so you don't risk that it will not be active when you use it and once opened it lasts super long if kept refrigereted in a glass jar. Also does not need to be proofed in water before using, which is an advantage for novice bakers.
Salt: High quality, unrefined sea salt from the Mediterranean seas will add a special taste to your bread. Using generic salts will not compromise the success of the dough in general, but using a real sea salt will definitely give you an extra edge to achive a fully earthly and aromatic bread.
Different recipes will call for different densities in the dough, but in any bread recipe a dough that is too dense and dry will result in a heavy bread, too compact inside and not crusty on the outside.
Especially when it comes to baguette baking it is essential to keep the dough runny and moist as possible. This will ensure a baguette that is airy and light and yet crispy and crunchy. At first it may be a bit tricky to shape it if you are a beginner, but with a couple of trials under your belt you will soon master it and the result it's going to be worth it!
Also, let your dough rise a first time for about one hour when still in a semi-liquid state. This is achieved by mixing with the water and yeast just half of the full flour quantity the recipe calls for. Once you let it rise like this for about one hour, you may add the rest of the flour and let it rise again. This will produce a dough that will be a bit more sour and lighter.