Gear System To Increase a DC Motor Torque

A Few days ago, i wrote about a job to made a line follower. After i was making the job, i was getting problem. To making the line follower, i was using dc motor. But, i was geting problem with torque from it. The DC motor is used can't give me enouh torque. i am confused about how to increase torque it. i was thingking about it. And i was remember about search engine, why i am not looking how to incresae torque from a dc motor at search engine ??? And then, i am looking from search engine about how to increase dc motor torque. i was founding solution about how to increase torque it. To increase it, we can use system gear. But, i am confuse how to aplication sistem gear at my line follower.