It all just depends. I've found that longer works such as concerto movements I would divide into sections to accomplish within a time period (given that you are either swamped with repertoire or completely open to starting anything new) and put a sticky note saying week 1 (first page) week 2 etc. keep a notebook, track your goals. To keep yourself focused, have things lined up as far as plans fir technique practice, sight reading, practicing new repertoire and polishing for performance, but put memorization FIRST. I usually start practice with warm up then immediately begin playing slowly and intently through each freshly memorized section, with the score in front of you (as you open the score and turn through the pages, run through the structure of what you memorized already, to make your memory more fluid, by recalling the entire piece over and over again in your memory...) open to the next section that is at task (do the mentally intensive work first) and if it still seems like a bunch of notes that aren't flowing very well, after memorizing both hands together, MEMORIZE BOTH HANDS TOGETHER FIRST, I SAY!!!!! then you go and practice each hand separately, at just a bit below tempo or moderate tempo being your goal (hands separate). This is usually my method, especially for fast pieces. you could also try hands separate, then hands together, then hands separate again. But do hands separate as first step, only if you cannot memorize both hands together right away. (though as a rule, you should aim for hands together memorization to become easy and unproblematic).
Also, write all over the score. I hardly worry about fingerings unless I discover something, then I write it down. I put an x next to lines of music that are repeating or signal a repeat, or how long a pattern is. OR I internalize it, but it is easier to internalize it by circling or marking, rather than using your photographic memory. That's how piano works-you memorize by playing the piano and you play the piano by internalizing information hardly relevant to the physical act of pressing down the keys...