As explained in a previous focusing tip, an alternative to the 'focus and re-compose' method is to use one of the other camera focus areas instead of the centre one.
Different cameras have varying number of focus areas and many cameras allow you to change the number of focus areas to be used, via the menu settings. There are many variations, and you'll have to consult the dreaded manual to learn about your own camera. Here's some variations.
The problem with using the outer focus areas
Notice from the main image of the family that the outer focus areas are represented by a vertical line, rather than a cross hair. This is because, depending on the camera, some or even all of the outer squares are not as powerful as the centre square and may have trouble focusing in low light or when there is not a great deal of contrast (again, check your manual to see whether your outer focus areas have the cross hairs). So, bear in mind that if you're having trouble locking in the focus using an outer focus area, it's sometimes worth switching to using the centre focus area.
I can't remember which method I used, but it's in focus so I obviously got it right!!