You can practice almost any aspect of dance by yourself, except for leading or following skills. You can practice the steps you are learning, do them to different songs so you know how to vary your speed to the tempo of the song, you can practice any technique your instructor gives you (posture, how to use your feet, knees and hips, etc.). You can also look for a practice partner in your class or among other students at the same stuido (your instructor might help match you up with soemone). You can also start going to social dances at the studio or wherever they are available and dancing with different people.

Good luck! Enjoy your dancing!