Disclaimer: keep in mind that I don't get much native Japanese reading exposure nowadays (bout an hour or 2 of FF13 every 1-2 days is my reading exposure atm), and I'm still a beginner student myself.
I don't have any solid tips on "remembering" them. I think most of them are common enough that you will recognize them after enough exposure anyhow. That's how I learned most of them. I don't really pay attention too much to the hiragana stuff I read. I think the hiragana are so common that even the rather unusual-looking combinations will provide no problems when reading them somewhere, or remembering them. They don't for me anyhow. It also helps that I hardly ever see hiragana used for those really wacky foreign sounds/words that katakana is used for, which is what gives me the most trouble.
Katakana is a bit different imo. 90% of the katakana I see right now is from videogames, so a lot of those unusual ones (like va) come up pretty often. Reading them and recognizing them is easy enough. Once again, enough exposure really should take care of the memorization of them.
The only thing that stumps me is some of the pronunciation. Like, I know クレジットカード is credit card, but is it pronounced like kureditto kado or kurejitto kado? Another one that bothers me is ゼリー. Is it pronounced jeri or zeri? I go with kurejitto kado and jeri for now, because I have no clue. I know the v sound is pronounced like a b, which makes sense because they sound pretty much the same when spoken quickly (and because I hear it endlessly on FF13), but for instance; zeri doesn't really sound like jeri at all to me. I haven't heard a lot of those other weird katakana sounds much yet, so I've never been sure on how exactly they're pronounced.
The only book I have that briefly mentions foreign sounds like this doesn't really make any sense to me when it comes to pronunciation. It lists ディ as di and ジェ as je, so why change them around to ジ and ゼ?
tl;dr
I think they're common enough that enough time and exposure will make them easily remembered without much effort. Also, I hate katakana