Summarize this article:

The settings you entered above are great for practice, but pro surfing servers will use much less forgive settings. Once you're familiar with how surfing works, change the sv_airaccelerate 800 value to sv_airaccelerate 100. You can decrease it in increments until you reach 100 so that you can get used to the slower air acceleration speed. Big jumps may look cool, but they'll kill your forward momentum. If you're trying to get the best times, you'll want to stick to low jumps to clear the space you need while maintaining your speed. The longer you hold Space, the higher you'll jump. Try to just tap it to clear the gaps you need to get over. The one time big air can come in useful is if you've found a shortcut you can use or a part fo the map you can skip. This almost always requires a very high speed so that you can make the jump. Not all maps have skippable sections. The M3 shotgun is one of the best weapons to use while surfing, as it stays accurate even while moving quickly. It's meant for close range, so try to use it on players using the same surfing ramp as you.  Not all servers allow you to use guns and attack other surfers. Try to avoid automatic weapons, as the accuracy will be terrible. The same goes for single shot snipers, as you'll never get an accurate shot while moving. You'll lose all of your momentum as well, but this can be a good tactic if you've already messed up your jump. Be aware that not all servers look kindly on blockers, so you may get kicked if it's against the rules.

Summary:
Adjust your game settings. Avoid big air. Look for shortcuts and corners you can skip. Use shotguns if you want to attack other players. Block other players by stopping in front of them.