You can start at Gadgetzan and cut across the desert to start. Be sure to check all the rocks and croppings along the way. The place is dangerous with alot of spawns. Travel along the edge, and then back along the outter boundary circling the map. Thistleshrub valley also has a few hot spots along with Un'Goro crater, Zul'Farrak and the areas close to Gadgetzan. Mining mithril may be a bit hard at low level, but the having the copper and tin will help you get some extra gold to spare until higher level. If you're level 50 you should be able to farm mithril fine. Just be sure to sell your stuff in the Auction House in smelted stacks. The Buy out option is one of your best advantages when you sell so make sure you use it. It's usually best to smelt copper and tin into bronze or vice Versa.

This is a simple tip on how to make money at low level.Durotar has the highest number of copper veins so would be the most ideal place.It may take about 1 hour to get to tin level so its not too bad. However tin is a little more aggravating. Near ashenvale there is a place with harpies that has a few nice spots. From their stick to the wall and go south, head over to South Barrens. go around Scorpid, Bristleback and Razormane and you should be able to level your tin in no time. You will need to become a Journeyman miner to begin.  Once you've collected a good amount of copper ore, return to the forge and smelt them. Once your copper ore is turned in bars, follow the path from Razor Hill north to Ogrimmar and then head to the auction house. Would be easier if you were an Orc or Troll because of their starting location. Orcs and Troll starts in durotar, for other races you will need to travel a bit further but it should all work pretty well. Be sure to check the going price and figure out if selling the bases or the product will sell for more. Lower level mining skill of course wouldn't make you as much as being on top of the chart and we know it may be a little difficult or frustrating to level.