I'm reading Folland's Real Analysis to learn some basic functional analysis. I read through his section Normed Vector Spaces and could make my way through most of the exercises I attempted. I am reading through the next section on Linear Functionals (dual spaces, Hahn-Banach) and am finding the exercises very difficult. I had glanced through Folland's sections on measure theory and found the exercises rather easy; I though this book was at an appropriate level.
I know Folland is more of a general analysis book; I just want to learn some of the basics (the cornerstone theorems, Hilbert spaces, Lp spaces) and so I did not think it necessary to delve into a specialized book. Is there a step down from Folland that still covers this material thoroughly-but-not-too-thoroughly? Or does anyone have any recommendation for a place to find easier problems to get myself started before tackling what I think are harder ones in Folland? The books I have seen seem to be beyond my level (e.g. Conway) or more applied books that may skip out on some of the theory (e.g. Luenberger). Perhaps my problem is just that I do not have much of an intuition with this material!