That's a GREAT FANTASTIC drawing!!!
For a smoother finish, you could use a paintbrush and go over your areas you want smoothing in the direction of the hairs. This is what I do all over my entire drawing. I never used to blend, but I've been experimenting since taking up drawing again and now use blending quite a bit with different textures and equipment.
I do use the putty eraser aswell for highlights and mould it to a point and then 'stroke' my highlights out. But then I go over my highlighted areas again with more pencil and then apply the eraser again and so on... I use alot of layering in my drawings.
The smoothness of your drawing will also depend on the grain of your paper. Have you experimented with different papers? I've found alot of artists that I've personally ran into are favouring smoother paper over more 'tooth' for realistic pencil work. But each to their own of course! Everyone is different and will like different materials.
At the end of the day, the best advice for anyone is just to keep practising and experimenting!
Good luck. Do post more of your work.