Start with raw red meat, bone marrow or raw butter, and honey when switching over from cooked to raw meats. The first day completely raw is an interesting experience. Takes a couple days to get used to it, including the lightness in your stomach when eating meat meals. You may even find it difficult putting down the entire meat meals, that is, 5-8 oz. of raw meat in a single meal the first few days as you adjust (it feels very satisfying/filling without heavyness). It smoothes out though quickly and you'll get your full appetite back over the week.
Wait for raw chicken until you've gotten used to the above aspect and raw red meat + raw fish on a frequent basis. At that point, raw chicken will be a breeze. Especially if you try high meat for the first time before you ever try the raw chicken. For me, high meat was scary the first time, but raw chicken was a sinch (I'd done high meat before i did raw chicken). If you know any local PDers by you, they might be able to hook you up with really nasty high meat so you don't have to wait so long for your own to get ripe.
Ground beef is a great suggestion first time round. But honestly, thinly sliced beef is heavenly, so go with the latter and let it get nice and warm before eating. Some guys I know really like to put meat with butter and cheese (unsalted raw cheese with meat meals with help remineralize the mouth according to Aajonus) on a ceramic plate, put it on a stove top on extremely low heat and let it get warm enough so that it melts (like an alfredo sauce) and they claim it makes the meat and whole dish taste exactly like cooked does. Especially for fish which is extremely hard to make taste great. You may find that even more appealing. You could also leave it in the sun instead for a very short period of time, just until it's melted. That could take 5-10 minutes, maybe longer if the sun's got coverage.
