"Now I should have a large town to my 2 o'clock, a woodland area and high ground to my right and a lake about 9 o'clock.
The big problem comes... which I think is the point others have made... when you can see a large town in your 2 o'clock with a wooded area and high ground... but the lake seems to have disappeared... You'd be amazed how easy it is to be fooled into accepting that you're still on track (been there, done that!)
One tip I was given was, for what it's worth, when planning look for funnel features i.e. a river coming in from your right hand side and a railway to your left, crossing over a bridge ahead. You should be able to pick up the line features sometime before you approach the bridge and so reassure yourself that you are on track?