My first map i am going to complete(some day). There is still much more to do, but here are first pics of it. I don't even know what i should add there, but i think i'll make it out.
I wonder tho, in order to make a map you need to know what type of map it will be. With a map lke that its kinda hard to find an objective. What could happend are cts come in boats and rescue hostages or the ts come to plant the bomb. I would consider to try to find reason and then base your self on it. If any of you are real HL2 fans you would have read on Raising the Bar that in order to make a good map you need to test playbility first instead of making a whole map with perfect textures and s**t then you find out you dont like and have to change it all over. Focus on the floor plant, have things to make a fun map with cover from various places and with a range of character levels, dont make a map thats easy if you have a sniper or something because it looks good. Have a variety of positions of attack and im sure you will get good rating on it.
Good Luck
Vary the terrain texture especialy around the volcano. Use a texture winth the work blend before it and paint alpha. Read the tut on amkjing a tunnel for more info.