Take sketching classes online at sites such as Udemy.com and DrawPJ.com. Both sites offer several resources for artists of different skills levels, including lectures, instruction and critique.
Education site Udemy.com offers an online drawing course that teaches the basics of drawing and sketching. Throughout 28 lectures and nearly six hours of content, the course helps students master the main concepts of drawing, such as materials, processes and devices.
DrawPJ.com is an accredited online drawing course that is useful for beginner artists, students preparing for advanced artistic education and experienced artists looking to brush up their skills. The site offers a number of different courses, including self-taught lessons, introductory classes and one-on-one instruction with private drawing instructors.