"My biggest struggle is the presentation process. There is usually a client that has a 'problem' with what I have created and often want me to use their own end result instead. Sometimes I just want to do my own thing and see if they like it, since they are not the professionals and I am supposed to be, but I am there to please the client.
What can I do to get them to respect me and my work?"
This problem for every designer as some stage of their career. It comes down to believing in your own ability and then convincing clients.
You have to be quite firm and explain from the beginning of your working relationship, how you work - Here is an example of my own process.
You are the professional in your field, they are the professional in theirs and as they have come to you, they clearly like what you do. So be clear and ask them to trust you in the same way that they would trust any other professional like a doctor, dentist, electrician etc.
For too long I used to want to collaborate with clients, but that isn't their expertise and often the work was always average because it was full of compromises. But I'm warning you now, some won't get it and won't accept it. But these aren't clients you want to work with, so make sure you can filter out these types in the future.
That is advice for the future, to deal with the current situation you will need to be patient and explain the entire process that lead you to a final solution to the client. When I present my work, it is in the form of 30+ page case study. I present this and I am there to go through it and answer any questions they may have.
Often once they understand, they will buy into what you have done because they can see that you have spent time considering their needs and goals.
It's a bit like when you tell off a small child. If you just say "Don't do that!" without the explanation, they get frustrated. If you take the time to tell them why they shouldn't be doing it, they are far more likely to comply and stop without the need for shouting or more arguing.