Car hire can be a daunting task, since there are many things you need to consider before deciding what car is right for your travel requirements. With the financial crisis giving everyone a hard time, you probably want to stick to your budget and, if possible, save some money on your car rental deal. This is why we have compiled a list of some ways to save when hiring a car when traveling to London or any other location for that matter.

Source
Book in advance
Even though you might find a great last minute deal when hiring a car, booking in advance will provide you with a greater car hire selection and better pricing. Once you decide on your vacation plans, book the car rental. Not only could waiting until the last minute get you stuck with higher rates, but also make it tougher for you to find the vehicle that you want.
Shop around and compare
With the Internet being at the tip of your fingers, you should profit from the opportunity to compare the car rental companies in your selected location and see what deals they offer. Be sure not to compare pricing alone, but also what is included in the price. This website provides a great comparison tool you can use for free in order to get the best offers and rates by simply entering the required travel information.
View different locations
When getting quotes and rates, also view your options for other locations that you can easily access. The location can influence the price that companies place on their rental packages. For instance, airport locations have higher rates, so remember that you may find a cheaper rental package for a location that is in close proximity to your destination.
Consider the car size
If you do not really need the larger car size, an economical sized yet spacious vehicle will save you a lot. A smaller car will come at a better price, but it will still provide you with all the room you need. Moreover, it is more economical, so it is perfect for city driving and will save you on fuel costs, as well.
Know the fuel policy
When reading the contract, make sure you pay a special deal of attention to the fuel policy and be aware of all the specifications regarding this aspect. For instance, many companies have a “pick up full, drop off full” policy which will require you to return the vehicle with a full gas tank. Otherwise, you will incur additional charges.
Age of driver
Most car rental agencies require the driver to be at least 25 years old. For drivers aged between 21 and 24, car hire suppliers have a tendency of imposing an age surcharge that can vary from $8 to $32 per day. So, if you have two or more capable and licensed drivers with you, make sure the nominated lead driver is aged 25 or over.
Be on time
It is recommended to arrive in time for your booking when both picking up and dropping off the vehicle. If you are going to be late, contact the supplier and let them know about your situation. If you are traveling by plane, provide your flight number when booking the rental. By doing so, the supplier will be informed on any flight delay that may occur.

Source
These are the most important aspects you need to consider if you want to save on your car hire. If you are traveling to an unfamiliar location, you should also take the time to get informed on the local road rules. In this way, you will better navigate your way around and will have a fabulous time.