This string specific website has lots of great resources for working on different skill-sets. I particularly like this for the finger pattern exercises and rhythmic reading tunes. This helps to work on rhythm, intonation, sight-reading, and scale work.

This site is a fun way to get students to start listening for specific intervals! It is loaded with different song examples for each interval. This can help students develop their ear training skills.

This has a list of important classical composers and a few important facts about them. This could be a great tool for printing out a quick "composer of the week" type of activity where students learn a little bit about specific composers. This works on their music history skills.

This is the entire American Folk Song collection. This excellent resource can be used by educators to print out folk songs to use to teach their students specific music skills such as singing, audiating, pitch, and rhythm. The website even gives activity ideas to use for each specific song.

This is a quick way of printing out sheet music for students. If students want to print out sheet music at home, they can use this website. This helps encourage students to work on compositional skills. It has different pre-sets for different instruments.

This website is a great tool for students to work on their music theory and ear training skills. Students can work individually on this website to complete different exercises and review music theory concepts.

This is a great resource for all music educators. The national music standards can be found here as well as information on scholarships, upcoming NAfME events, and articles for teachers. This can help teachers help students in all aspects of their music education.

This is a great resource for free sheet music for students. It offers a variety of instrumental music of all kinds of genres. Students can also use this website to explore music on their own and develop sight-reading skills.

This is a great, free metronome tool to use with students in the classroom or for them to use in their own practice at home. It allows students to work on rhythm, tempo, beat, and time signature.

The American String Teachers Association is filled with helpful resources for string teachers specifically. The "teaching resources" page includes tips for working on string specific content such as bowing technique and left and right hand position.