Some people spend a lot of money on a fancy vacuum cleaner, but when it comes to effectiveness, a modest vacuum cleaner that is well maintained can remove more soil than a higher priced vacuum cleaner that is neglected. I am not going to pretend to know everything about all makes and models of vacuums, and therefore I should say that some of this may not apply to your vacuum. Here are a few very simple things to keep your eye on, regardless of the type of vacuum cleaner you have.
1. If it has a belt, learn how to check the condition of the belt and change the belt when it becomes damaged or stretched out. This will probably need to be done about every 1-5 years depending on how much use the machine gets.
2. If it uses paper bags, change them more often than the bag suggests. A bag that is only half full will have a lot less suction than a new bag simply because the surface (pores) of the bag get clogged and reduce air flow which in turn reduces suction.
3. If your vacuum has a canister, dump it frequently. Allowing it to get full only increases the amount of dust that begins to collect on the filter.
4. If your vacuum has a canister, be sure to check what other filters the machine has. Virtually all vacuum cleaner will have one or two different types of filters in addition to the canister. Some people go years without realizing that one or two filters are restricting the air flow dramatically. Many of these filters are washable and reusable. Consider purchasing a spare. That way you can place a dry one in the machine at the time you take a dirty one out to wash it. Make sure the washable filters are 100% dry before putting back into the machine.