I’m having a really hard time with the honorific and humble forms at the end of N4. I never know if I’m supposed to use the RU or the MASU form. They questions don’t specify if I should use a polite form. I’m also finding the questions very difficult in general for what exactly they are asking for. Does anyone have any tips on how to know which form I should be using?
Otherwise, this application is great. I went ahead and bought a lifetime sub. Best grammar tool I’ve used.
What’s RU form? Do you mean dictionary form? You’re going to use either an honorific or humble form, so there’s not necessarily a dictionary or masu form to use. Where relevant, you’ll probably want to use masu/desu.
It would help us help you if you posted a few specific examples that are causing confusion.
My only other suggestion is to reread Tae Kim’s explanation of honorific and humble forms. I had to read it several times before it started to sink in.
I can look over them again, but just going over my reviews again and the example sentences it’s hard to understand which phrase to use when. I think my biggest issue is いらっしゃる since i get confused when to use this form rather than the TWO different forms of TO DO.
Everything else on this site I can learn with a little bit of practice, but I fail this section over and over and over again. ugh…
Generally, when using 敬語 and the word is at the end of a sentence you are supposed to use ます/です forms like @seanblue says.
If it is quoted (日本語を教えていらっしゃると聞きました。, before と) , used to qualify nouns ( こちらの商品に お求めになった お客様, bolded word is the qualified noun, subordinate clause) etc it is should be used in a short form.
Like typical verb 
いらっしゃる has the meanings of all, 来る(to come)、行く(to go)、いる(to be). It can be freely swapped with おいでになる (does not apply to ている grammar which becomes ていらっしゃる, and you probably meant it as “to do” since it means “is doing”/“is in a state”/“has a hobby of doing”) , since it has all of those meanings too. It can be also changed to お見えになる, but only in “to come” meaning.
By the way, there is another 敬語 word for “to come” - お越しになる. 
If you want to say “to do” instead of する you can use なさる or される (passive can be used to create honorific expressions, so-called easy 敬語 (a lesson about this will appear on bunpro)).
thank you for the response. I’ll take another look at my reviews and see if I can make sense of it now.