I'm not clear what you mean by "angle when you strop". When stropping, the spine and edge should BOTH be on the leather (or whatever) through each stroke, and the blade flipped, on its spine, and then taken back the opposite direction, spine always leading and edge trailing, but with both fully contacting the surface. Some strop toe leading or do X strokes, but at least at the beginning I suggest just going up and down the strop if you have a 3 inch strop, and in a subtle (not angled and exaggerated) X if your strop is narrower. Gentleness of your stroke and tautness of the strop are also keys. Go slow, go steady, go without more pressure than it takes to stay in contact with the strop. Barring a faucet ding, bad stropping is the #1 common cause of degrading an edge.