Bot games are good for learning to last hit and some basic skills but besides that everything you learn will be from playing against other players. If you are new to DoTA I recommend watching
Purge's videos, he reflects over what he does usually and can help you to become a better player. Also, losing is just part of the game and you shouldn't be discouraged by the extremely high skill curve. Some of Skial's top players including me, Faron, Sven, Gator, etc. have over 1000k+ hours of DoTA and we still have things to learn.