Dryer not drying clothes very well

You have some blockage between lint trap and where the unit vents outside.

most of the problems associated with this problem are caused by lint being in vent tube to outside and restricting the air flow. clean out vent tube, from dryer to outside. this should help. repost if need be. good-day ! if you have too. clean out bottom of drier with a vacuum. around the fan and where theres lint trapped.

Overloading
1. One of the simplest problems to remedy could simply be that you are putting too many items inside the machine during the drying cycle. Avoid overloading your dryer, as this might cause your dryer to work extra hard to dry your clothing, extending the length of the dry cycle.
Wrong Heat Setting
2. A common issue with clothes dryers could be the wrong heat setting. Most home dryers feature several settings, from low heat settings to high heat and permanent press. Be sure the setting you choose is right for your needs. Another setting to check is the load size of your dryer. If you are drying a large amount of clothes, be sure the setting for large loads on high heat is selected. Choosing the wrong heat setting or load size can cause your clothes and linens to take longer to dry.
Lint Trap
3. One of the simplest fixes for drying issues might just be that your lint trap is clogged. Each time you use your dryer, lint will form in the trap. If the lint trap and vents are full, this could block air going into your dryer and slow down if not completely stop the drying process. After you use your dryer, remove this lint trap and empty it fully. Even if the lint trap is full, your other dryer vents might be clogged as well.
Clogged Vents
4. If your clothes are in the dryer for a long amount of time, but still not drying, the reason for this could be a clogged vent. A sign that your vent is clogged is if your clothes are warm or hot to the touch after sitting in the dryer, but still damp. To unclog your dryer vent, you may need professional assistance. This is especially necessary if your dryer vent leading out of the house is particularly long.
Heat Source
5. If the dryer is not getting enough heat to dry your clothes,something could be wrong with the heating system. After the drying cycle, touch your clothes to see if they are warm. If not, this means that the heating mechanism is malfunctioning. It will need to be repaired or replaced by a professional.

First you should make sure the exhaust vent and ducting and lint trap is not clogged or restricted, birds/insect nests, or lint build up. If the dryer is heating up it is most likely an airflow issue.

This is a potentially deadly scenario. If the clothes are warm but just not getting dry, there is a problem with air flow - specifically - the lack thereof. The chance of fire is a real concern.

Make sure the lint baffle / trap is clear. This should be checked / cleared after each drying cycle. Most folks know about this, but I included it just in case this is your first dryer.

If the the baffle / trap looks clear, the exhaust tubing of the dryer is suspect. Many installations consist of the flexible / expandable hose. This hose may have become crushed during the running of the dryer, reducing air flow. Locate the hose and pull the dryer away from the wall to inspect, expand or replace the hose as needed. If an old installation, it is very possible that the hose has become clogged with lint build up over the years. The hose should be replaced in this case.

If at all possible, use aluminum expandable dryer duct. It is less likely to collect lint as quickly as the flex plastic style.

If the clothes are not warm or hot, the heat source (electric heating element or gas flame - depending on type) has a problem. Either of these problems should probably be referred to a pro for proper repair.

Sound like the air is trapped in the dryer. Is your lint trap empty? Is the dryer properly exhausted and the ductwork clear of lint or obstruction?

is your lint trap and exhaust hoses clear and unrestricted???open up dryer and clean out lint,then do the same all the way to the outside where it exhausts

clean vents, including exhaust vent

IS THE DRYER PUSHED UP AGAINST THE VENTING IN THE BACK OF THE DRYER? IT MAY BE CRIMPING THE EXHAUST MATERIAL CAUSING A RESTRICTION.

IF THAT IS O.K., DISCONNECT THE EXHAUST AND RUN A LOAD OF LAUNDRY THROUGH A NORMAL DRY CYCLE.
IF THE DRYER DRIES THAT LOAD O.K., THERE IS A RESTRICTION SOMEWHERE IN THE EXHAUST. ALSO, CHECK THE LINT TRAP. IF THERE IS A WHITE CLOUDY FILM ON THE LINT FILTER, TAKE A WIRE BRUSH AND CLEAN IT OFF. IT IS RESTRICTING THE AIR FLOW AT THE FILTER.

CHECK THE LINT FILTER HOUSING FOR A BUILD UP OF LINT. IF THERE IS, USE A CENTER CARDBOARD FROM WRAPPING PAPER ATTACHED TO THE END OF THE VACUUM HOSE. FLATTEN THE CARDBOARD TO FIT INTO THE FILTER SLOT AND CLEAN OUT THE LINT.