I usually make my own MMF and combine it with some Satin Ice. I use a silicone mat to roll it out on and do not add cornstarch or powdered sugar.   I just can't seem to cover my cakes as nicely as I would like.  They are OK and customers haven't complained, but I know that they could be a lot better!  I feel that when I cover my butter cream frosted cakes that there are always air bubbles and sometimes my fondant wants to start sagging.  Also the finish of my fondant is not as silky looking as I would like.   Should I not use MMF?  Suggestions?  I have attached a recent fondant cake that I made so that someone can give me some constructive feedback about this cake.   I won't be offended,  I just need to know how to make this more professional looking so that I can increase the demand for my cakes.

I think your cake looks pretty good!  How thick is your layer of buttercream under the fondant?  You don't want it to be too thick.  I refrigerate my cakes before covering with fondant.  It makes you buttercream firm and it's easier to smooth your fondant without the buttercream moving underneath of it.  I still have problems with getting air bubbles under the fondant, I haven't mastered that yet!