Here are some fantastic videos to practice vowel and consonant sounds, especially the Sounds American channel.
Here are some helpful websites to practice segmentals and suprasegmentals.
Conversation Questions & Answers
Here are list of conversation questions about some of the topics from the Beginner English courses.
If you can ask and answer many of these questions clearly, you'll really improve your English.
Grammar Websites & More
Here are some helpful websites to practice grammar at all levels as well as other skills, especially the first one.