this: This seems discussed a lot. Do not send away your early units. If a scout finds your city, trap it between your city and the unit. Stay away like three tiles with your warrior, if the scout gets in, cut his way, if He comes out attack him and Stay at your hex. Heal one turn, he runs back twoards your city and back, kill it.
very good tactics, always works. just kill the messenger before he runs the marathon back home..
what i just do is spam 4 slingers and a warrior. if you dont want them to come back (i.e. new camp), make sure you see all the tiles round your lands. most of times it is however very useful to constantly have a barb camp somewhere. advances, money etc.
i never defend capital (i play deity, 20 civs, marathon, max CS, max volcanos, fractal). just try to get as far as i can for huts and CS's. it doesnt matter, if an AI wants you and is close it will kill you anyway. even with your first warrior its not enough, so i dont bother anymore. as soon as i have 2 slingers and 1 warrior i know i will survive... so scout like hell with warrior and spam slingers,...