Took me around two weeks to have the kana down. Just make up mneumonic devices for each kana until you don't need it anymore. If you have funny mnemonic that makes you laugh when you think of it I guarantee you won't forget that character. Since it was awhile ago I've mostly forgotten all my mnemonics, but here are some I remember:
と to(it's shaped like a 'toe)'
ラ ra(it looks like a mouth going 'RAA!!')
こ ko(it looks like a knocked out person's face, 'K.O.')
く ku(it 'coo' cuz it da easiest hiragana to draw!)
ち chi(the bottom half is a backwards 'C', Chi)
り ri(they looks like 'reeds')
ノ no(there are 'no' other strokes)
マ ma(it looks like the head of a 'martian')
ヒ hi(it looks like a person sitting and waving 'hi')
ム mu(this reminded me of a cows nose, cows go 'moo')
れ/レ re(these looks like 'rays' coming down)
て/テ te(these look like the letter 'T')
Yes I realize that these are very funny/odd mnemonics but they must have worked pretty well if I can still remember them

Also, a good suggestion is to make flashcards, and find sheets of romaji and translate them into Japanese. Hope I've been of some help!