I've been mapping for a while now, around a year or so. Most of the mapping I've done has just been creating simple no objective maps for my friends to screw around with on their servers. I started playing around with the core gamemode because I believed it was an interesting concept, but when I started making maps that were supposed to be competitive I quickly found out that I had no clue how to build a map with any sort of balancing. I'd like to get into more advanced mapping but I don't have the slightest clue where to start. I know a decent bit about mapping - I can make working maps, entity logic is something I understand and I know not to carve - but I know next to nothing about the things that take a map to a professional level. I only have the slightest understanding of what the skip and hint brushes do, my maps are an unoptimized mess and I haven't the slightest clue about how to balance my maps. Could someone point me in the direction of some good tutorials about how to take my mapping to the next level?