What makes a good fuel?

A good fuel may have one or more of the following characteristics:
High calorific value: it should be able to generate a high amount of heat per unit mass (or volume). That would enable generation of a higher quantity of energy per unit.
Low cost: the fuel should be economical to manufacture or extract. This would ensure that it would be used for more applications and by more people.
Longer shelf life: a good fuel should not degrade over time and hence be amenable to long-term storage.
Easy transport and storage: a good fuel does not require too many precautions or considerations for transport and storage, thereby keeping the costs low.
No or low level of emissions and products: a good fuel will produce no or a very low amount of emissions and products that require disposal. This also means that no harmful emissions or end products should be leftover so that the environment and living beings are not adversely affected.
Controlled combustion: the fuel should be amenable to controlled combustion so that it can be used in the desired manner as per our requirements.
Moderate ignition temperature: the fuel should have a moderate ignition temperature, thus ensuring energy generation at moderate enough temperatures.
Hope this helps.