- It depends on the type of text. For example in texts about a soccer game, you will stumble on a big amount of katakana words because a lot of English loan words are also used in Japanese.
As for hiragana, it doesn't mather what the text is about. It is used together with Kanji to construct typical Japanese grammaire constructions and certain words. Also texts that are supposed to be for little children, will have Kanji with furigana on top of them; this is a small hiragana script that will make it easy to read Kanji without knowing any Kanji readings at all.
- As for reading/recognizing, it must be hiragana because there is more difference between all symbols. As for writing, katakana is probably easyer because the symbols are more symplistic.
- repeat, repeat, repeat. Write them down out of your head, and try to recognize them.
- I think it makes more sense to start with learning hiragana, but you should learn both.