Hey Belén, i came across this question myself in my studies a few days ago so I thought i'd share what I think about it. I'm not completely sure, but at the moment, i think the difference is that you use verb+gerne for things that you already have done and describe a preference for. I think gerne even means not just gladly but 'preferentially', literally. So, 'ich trinke gerne bier' would be for if you are a lover of beer, but 'ich möchte ein bier trinken' would be for placing an order, asking for it. With 'ich würde gerne' it might be saying what you would prefer in the future. What do you think? I'll ask one of my German friends.