Hello!
Sometimes it’s the simplest things that are the hardest to remember…
I am always mistaking 八 for 入 (strangely not in the other direction?) which is keeping me from leveling up! Does anyone have experience with mistaking two Kanji? How do you deal with situations like this? Do you make up your “own” mnemonics/explanations for the difference? I am asking because I guess that this will happen more often later on 
This is acutally my first post here, sooo - はじめまして！
To remember this, it may help to know that 八 is the progenitor of the katakana character ハ (which is also the first syllable of はち).
Interesting suggestions!
I haven’t seen the similarity in ハ and 八!
Maybe I should also think that 入 must be closed, because it is a tent you enter, and if the tent is not closed, it will be useless if it rains…
Not even joking, when I have leeches like that, I write them on a whiteboard that I see every morning as I go out the door. I’ll generally erase it after about a week or two. Increasing one’s number of exposures to the item may prove useful for some. i.e. Me.
Wait until you find out that 人 and 入 are written differently than the fonts. One slants left, the other right. 
On a related note, I have a major problem with 輪 輸 and 論 諭 
八 and 入 are relatively easy to distinguish, just remember that in 入 the lines are touching, and in 八 they’re more spread apart.
Or the similarity in the radical for dirt and the one for samurai. Damn those radicals.
That’s when start to understand that the length of your horizontal lines really matters
I kept getting those mixed up too until I realized that 俞 is a phonetic component read ゆ.
Wait until you use kanji handwriting IME on your phone and try to see if the system interprets your horizontal line as 一 (one) or ー (katakana long vowel indicator/chouonpu).
Other fun characters: 二 and ニ, 夕 and タ, へ and ヘ, 力 and カ, 才 and オ.
Hahaha I mean “straight up” as in “word” , “I feel you” - it’s a hood expression haha. Didn’t realize how confusing it will be since you were talking about orientation. My bad XD
Nono, I know.
I like to derive humour by faking confusion sometimes. I guess it could be…confusing. 
