When deciding to adopt:
1) You may wish to visit your village frequently, to see the change taking place first hand. In that case, make sure that you pick a village according to your physical capabilities, as many villages can only be reached on foot or horseback.
2) Know your available budget. There is always a village that fits your budget as you can also join other champs.
3) A step at a time. You only pay for one year though three years are needed to produce sustainable results and change the lives of the entire population for good. Check the progress during the first year and only contribute the following years, if you are convinced that your contribution has benefitted your village as expected, or more.