ぬ、め are actually easy to differ. I made them clear to my self so that ぬ is the hiragana of いぬ so dogs tail is in ring.. similar to pig's tail. other is without that loop. But sometime it's still difficult. about katakana I better don't start complain yet. Because I have only learn some very few.
I have tried also to practice to write hiragana with pencil to paper and also with computer by using a tablet, but my handwriting is so ugly, that It makes me depressed to see it. In general I try to avoid to write by hand only when sing some time some document.. or when I'm really forced to write something I use these shifted romanji letters used to start a sentence.
I think you want to say "I goofed off again." If so, you should say また rather than もういちど.
Yes I wanted to say that I goofed off again. So then. ぼく は また れんしょう を なまけました。
プーチ の そうすいかん が また こわれていました。 それで みんな は おゆ が ありません。
Actually one very hard thing is to come up with good sentences, that I'm actually able to but into Japanese. It's no point to go straight to too difficult sentences that I don't understand at all, but I can't also say things like たんぽぽ は いぬ たべた。 (Dandelion ate dog.) for ever.
きょう、 わたしち は けんざい の みせ を いきました。 くぎ だの ラッカー と モンタージュフォーム が かいとりました。(Today we went to shop of building materials. We bought things like nails, lacquer and montage foam.)