There is no english equivalent of the 'ch' sound in loch. Yahalome Tal, who comes on this board proposed the easiest way to pronounce this I think. Go to back a 'k' sound, and push air thro ur mouth, not vibrating the air (keeping it unvoiced) but instead of making a k sound in the middle of ur mouth, make it at the back of your throat. It's closest relative phoneme is the French 'r'. I don't know the sound, but if you do, they are related. The 'och' is harder to pronounce I think, so try 'ach' for starters, it is easier to say. Like the Gaelic word 'Sassenach', meaning 'outsider', someonw who is not Scottish. I hope this helps.