You depend on your AC when the outside temperature rises, so it can be a major issue when it doesn't cool well. The following are some reasons why this can happen.
#1: Fix the fins
Poor cooling is often the result of the condenser coils being unable to transfer heat and cool air properly. These coils don't actually look like coils. If you examine the outdoor part of your AC unit, you will see fins which resemble a vent screen covering at least one side of the unit. When these fins become bent, your condenser doesn't cool efficiently. Fortunately, you can purchase fin combs from any hardware store or HVAC dealer. Carefully draw the comb along the fins to straighten them out. Keep in mind the fence are very thin and can cut you easily, so you may want to wear leather gloves for this task.
#2: Stay on top of the filter
The filter systems within your AC unit are there to keep dust, pollen, and hair from clogging up the fan and motor. Once the filter begins to get dirty, air flow is lost to the unit and it can no longer produce the cool air you desire. Filters should be changed every other month, unless you have pets, it's a high pollen count year, or it is exceptionally dusty in your area. In this case, change the filter monthly during the cooling season. When changing the filter, also check the filter housing, as sometimes loose dust and hair collects inside of it. Use a vacuum nozzle attachment to clean out any loose debris in the housing before placing the new filter.
#3: Upgrade your thermostat
Your thermostat could be the reason you feel warm. An older thermostat may not be delivering the proper reading, which means your house isn't as cool as you think it is. You can test this by using an outside thermometer to read the temperature. A thermostat that isn't level can also affect the actual temperature that the AC is cooling to, so use a level to verify that your thermostat hasn't been knocked off kilter. Your best bet is to upgrade to a new thermostat, though. The modern digital thermostats allow you to program them so you can control the temperature of your home for all times of day, including when you are home and when you are away. This way your AC is only running when you need it to. Not only does this lead to better cooling, it also saves you money on your energy costs.
For more help, contact an HVAC company, such as Air Time Heating & Cooling, in your area.