Bamboo. .the method Bluebeard suggests is the correct approach. However using 2/3 the windspeed to give your estimated maximum wind drift (the expected drift if the wind was perpendicular to heading) only works at a TAS of 90 knots. At 120 knots the max drift is 1/2 the windspeed and at 60 knots (if you fly a microlight for instance) the max drift equals the windspeed. This is all based on the 1-in-60 rule for calculating angles from vectors and you can read all about this in the very excellent Trevor Thom book 'Air Pilot's Manual - Air Navigation'.. .. .From the estimated max drift you can then use the 'clock code' rule of thumb to work out your actual drift and wind correction angle. The clock code says multiply the max drift by the angle between wind and heading divided by 60. If the wind is 15 degrees off your heading 15/60=1/4 so use 1/4 of the max drift as the wind correction angle, if the wind is 30 degrees off the heading 30/60=1/2 so use 1/2 the max drift and at 45 degrees use 3/4 the max drift. At angles of 60 degrees or more you assume the actual drift equals the max drift you have estimated previously. . .. .This method is simple and works. Combine this with using a simple angle plotter and drawing a diversion line on your map so you can estimate a track bearing and then apply the necessary correction to get the heading to steer and you should have no problems. The most important thing is to get onto the correct heading as soon as you reach your planned diversion point. Once you are going in the right direction, and can confirm this with ground features that agree with the chart, you should then have time to work out the distance to run, your ETA and still have enough brain left to do your freda checks.. .. .Hope this helps - it worked for me - got my licence last November.