If you were moving from scrapbooking to just card making....

I used to scrapbook mostly. Card making was rare. That has been reversed, but I still use my 12x12 papers and other scrapping supplies for making my cards, along with additional supplies, such as for shaker cards. I was a stamper/card maker for about 10 years before I started scrapbooking, then I really got into scrapbooking. I still used my stamps occasionally for scrapbooking. Now I am back to mostly card making and using my stamps more (and buying more stamps) again. My storage for scrapbooking works just as well for card making. I have my papers in cubes, and sorted by seasons, color, basic patterns, and sometimes manufacturer. I don’t see a need to do anything different just because my focus shifted.

I might begin to buy differently

However, I would definitely look up ‘maps’ online of how to make 10-12 cards from one sheet of decorative paper ( plus cardstock ) there are some really good ones out there that use every bit of the paper. This way you could get the most out of what you already have on hand.

I’d suggest just using the tools you have unless you find them too bulky or that they’re taking up too much space. I started doing some card making about a year ago and just use the stuff I already have. However I found that I most of my stamps and dies weren’t really going to work to make what I wanted. I needed to buy a few phrases and some cute stamps (self enabling shopping excuse). Embellishment-wise I’m good since I’ve always preferred smaller stuff. I wouldn’t cut up all my 12x12 paper/cardstock because you never know.

As I’ve move into more card making and less scrapbooking I agree with this! I have noticed my shopping has changed in just these ways. 

And I also agree with @kendramage on my patterned paper. I’m able to use papers on cards that just didn’t work for me on layouts.

I liked pancakes recommendations.  Seems like Misti would be a big help especially.  Another good suggestion was a good paper cutter.  I also have some of my 9x12  cardstock packs cut in half at a Kinkos type place.  Just saves time.  Good quality cardstock and the right coloring mediums are good if you plan to add hand coloring.  I keep watercolor paper and Bristol on hand also for watercoloring.  

I think it depends on how much paper you have and what kind of cards you like to make as to whether to cut down 12” papers. In the beginning of cardmaking I did, but I didn’t necessarily know what I needed from the paper so I did (very mildly) regret some of the cuts I made. But if you have good guidelines (like the love it chop it or sheetload of cards cutting guides) you can make a lot of cards out of papers you would never scrap with. I needed to be able to store paper more efficiently and I didn’t have much so I did chop everything into 4” strips and then either in half at 6” or into 5.25” pieces. (At first I cut things into 6x6 squares but that led to a lot more waste).

A lot of the tools seem to work for both scrapping and cards.

I use a 6x12” guillotine trimmer which gives the flexibility to trim down full sized sheets but is also more functional for smaller cuts. BTW check if your trimmer makes cuts that are both straight and SQUARE. My little Fiskars was just off enough that every single card I made looked wonky. I thought I was terrible at cutting and glueing, but no, it was the trimmer. It’s much more obvious on cards.

A stamp platform of some kind is probably the best investment you can make into card making. Being able to double stamp or mass produce, it’s cut down so much on wasted paper and frustration.

Although getting card bases cut seems to work for some people my local office supply store did a terrible job and wanted to charge me way too much, so buyer beware on that. I would rather just chop my own Neenah than have to fine tune every cut that I paid the Staples guy to do for me. A proper paper/print shop may do a better job.

I watch and enjoy Kylie’s love it chop it too. But I don’t think I need the templates, I already have the common measurements that I use written down and taped to my desk. 

I’m mostly a card maker now.

I’m going to echo what Embri said above. Use that patterned paper white side out for envelopes. I rather enjoy making my own envelopes and an envelope punch board is a good investment.

I almost exclusively use solid colors for my base. I prefer a heavy weight cardstock, but since I have a bunch of ‘left over’ lighter weight cardstock, I’m still using it on occasion.

If you make your own cardbases, a good large scoreboard and bone folder are nice to have. There’s a thread around here someplace about bone folders. I got great suggestions from the Peas and bought a nice one I really like because of their enabling. Ha.

I would buy 6x6 paper pads instead of 12x12 papers because of the smaller pattern size on the paper itself, plus the ease of storage.

I use my old 12x12 papers for making envelopes, or for practice cuts in my Silhouette.

I own a ton of stamps for cardmaking but very few for scrapbooking. You need to get a good storage system going for your stamps if you plan to buy a lot (I use Jennifer McGuire's system). Same goes for dies.

I bought inks specifically for cardmaking that I wouldn't use for scrapbooking, like Distress Oxides, and dye inks. I use archival or pigment inks for scrapbooks.

I also like to have a lot of pre-cut card bases on hand. I did have Staples cut up a package of cardstock for me, but the girl that cut them did a terrible job and they're all off, so I pre-cut my own now in big cutting sessions in front of the TV.

Oh, and finally, I like to both use solid stamps and line stamps, so I have a variety of colouring mediums, too, like watercolours and pencil crayons - stuff I would not have bought for scrapbooking.