This website has a lot of puzzles in japanese as well as character practice. Some of them are in kanji and katakana but there are quite a few in hiragana as well. I've done most of the hiragana ones (except the crosswords) and I've found them really helpful. They are kind of hard but they actually are a lot of fun if you like puzzles. I spent about 30 minutes to an hour on each of them, so they don't take too much time. The website itself (first link) is hard to navigate so I put the most helpful puzzles to me in the links below. Directions are in the top right corner in small print of each puzzle. The writing practice shhould be self-explanationory.

Puzzle Website
Hiragana Writing Practice
Hiragana Logic Puzzle
Hiragana Cryptogram Puzzle
Hiragana Puzzlegram Puzzle
Hiragana Crossword Puzzle (with wordbank)