i'm in the middle of making a proper manual for the game. if you click on the world map at the top, check for lumbridge (where you start), al'kharid (in the dsert) and varrock (the really big one). if you follow the map to go north then east then south to al'kharid, find the silk trader and buy some. then go to varrock and sell them in the general store. it gets repeatative but gets you money for nothing (even with no skills).
next you should work on trade skills. mining is pretty good, go west out of varrock and travel pass the barb village then go north-west. go into the mountain to the dwarven miines, mine what ever you can (copper and tin to start) and then leave and go south-west in to falador. there is a furnace there where you can turn ores to bars, then go back to varrock and find an anvil, you'll need a hammer as well. turn the bars into stuff and sell them in the general store or sword shop etc.
sorry thats at lot to read but you'll be making money pretty quickly like this. hopefully my manual won't be long