* von meinem Deutschlehrer/ meiner Deutschlehrerin
* von meiner Deutschlehrerin is used if your tutor is female.
* von meinem Deutschlehrer is used if your tutor is male.
You could also say:
* bei meinem Deutschlehrer/meiner Deutschlehrerin - This translates more literally to "at my German tutor" and might be used in context like "I learned that at my German tutor's" (Ich habe das bei meinem/meiner Deutschlehrer/in gelernt).
The best option depends on the context of the sentence. If you can provide the full sentence, I can give you a more precise translation.