The SRS interval for apperentice is usuallly a week, so if levelling up is what you aiming for, then focusing on guru’ing the apperentice is the way to go. Theres also a setting in WK that sorts the reviews so that apparentice items are sorted first.
Read up the WK tutorials for more info such as how to unlock new lessons
But if more reviews you want, then you just have to do more lessons, add them to the review pile, and slowly go through em. You can do more than the alloted 10 per day, Heck, theres a post here in the forum about someone getting to level 60 in 1 year, roughly 1 level a week. Plus overtime, items in the master / enlightened should be back in rotation for you to review, hopefully burning them in the process.
Mad lads in question:
- My Journey of 368 days (+ The Ultimate Guide for WK
) - My Wanikani journey of 353 days, or what not to do
- At Wanikani end. 356 days to level 60
However, that being said. I do not reccomend at all rushing through the flashcards.. Especially pass level 15-ish (known difficulty plateu), as by that point the flashcards gets more abstract and harder to recalled, causing enlightened items to drop to apparentice, wasting 4 months of wait, and becoming “leeches” 
.
I do not know what your level of proficiency is, your JLPT level, how dedicated you are to learning JP, nor if you have any other sources of learning JP. But for WK specifically, i recc to set a review goal (like 80 reviews per day), only do 10 new lessons when the review forecast is low, and build a habit of consistently doing your reviews daily. Better to set a good habit early on and consistently stick to it, than blazing pass the first 10 levels, only to give up at level 11 cuz “i cant remember anything, i give up, this sucks”