The first thing to say is this: everyone is different. I went from being a porridge-worshipping fruit hound who carried a rucksack full of bananas and home-made muesli bars everywhere I went, to a fairly strict Paleo dude in the space of 24 hours. I read about it, it made sense, I did it.
My better half, on the other hand, has taken 3 years to transition. Chances are, you are more like her; but if you are more like me, then you can stop reading here, because you are so obsessive and single-minded about this sort of thing that you don't need advice on how to make the switch anyway.
To go Paleo you basically stop eating certain foods and eat more of others to replace the calories. The new foods will be more nutritionally dense that the ones they displaced - hence you get healthier.
So I recommend writing down a list of the foods you need to stop eating (e.g. potatoes, rice, bread, refined sugar) and a list of the foods you need to eat more of (e.g. meat, fish, eggs, nuts.)
You can use this as a reference as you transition, just to remind yourself where you want to get to. Beyond this, how meticulously you plan and document your activities is down to your own style. Do whatever works best for you.
For my other half, it was refined sugar. The great thing about this one is that you can get some pretty tangible benefits from that change alone.
The key is to pick these suckers off one by one rather than try to do too much. That way your sense of achievement that is not sullied by the fact you are still eating other non-Paleo foods. If you only aimed to give up one thing to start with, then you have succeeded.
As you start tackling the bad guys, you need to identify your allies amongst the good guys. As you transition to Paleo you will start to lose your treats. No more crackers with creamed cheese or potato chips in front of the TV. You will suddenly become aware of how emotionally ingrained some of the snacking habits you've developed over the years are.
For me, porridge was strongly linked to childhood. I still miss it now. But once I started exploring the Good Guys I realised I had some fantastic allies - and now I have even stronger bonds with Paleo foods and now I wouldn't give them up in favour of porridge or any other non-Paleo foods. My snacking allies are nuts, coconut (in its many forms) and seeds. Other allies are avocado and scrambled eggs.
You have some meat, some vegetables and some brown stuff - this was how I heard a young child describe mealtimes on a recent documentary. Clearly it depends where you are in your transition as to how much and which types of brown stuff you have with your meals. But as you start to pick off the bad guys like rice and potatoes, you need to start seeing meals as meat and vegetables only.
The challenge is then to be inventive and use variety to keep things interesting. Ever eaten a rabbit? Lamb's hearts? Venison liver? Fresh Crab? There are hundreds of types of fish. Indeed there are hundreds of varieties of vegetables too. And with the potential to throw coconut, nuts, seeds and fruit into the bargain, suddenly pasta seems a little dull - mere padding. This is how you need to think. Exciting recipes for Paleo meals abound on the internet.
Paleo is low carb, by definition - as you eat more of the good guys, you'll get more fat and protein. As you eat fewer of the bad guys you will get fewer carbs. Embrace this - it's why you can still get full without the brown stuff. It's why this diet is so healthy.
But fat is bad, right? Don't get me started on this. There is conflicting advice even from within the Paleo-eating community on what is the optimal macronutrient composition. Did our ancestors eat lean meat or fatty meat? What was the omega 6 to omega 3 ratio?
My advice is this: provided you eat meat from animals that have had a decent life (i.e. not been intensively farmed) then you can be pretty relaxed about fat intake from animal sources. Clearly there are other fats you should avoid, like trans fats and certain vegetable oils that are high in omega 6; but if you stick to the recognised healthy fat sources (nuts, avocado, coconut, oily fish) and as I say, animal fat from happy animals, you can stop worrying about how much you have.
But if you are in any doubt, do some reading. Empower yourself so that when the doctor or some other pseudo diet expert tells you your diet is wrong, you can smile smugly to yourself rather than inwardly panic.
I used to eat 7 meals a day. I was the Tupperware king. If I was more than 50 metres from a protein shake source while working out, I would panic. What if I missed the window? I sometimes got up in the night to eat nuts. Gotta stay anabolic! I would obsess over glycogen replacement and guzzle energy after workouts.
When you go Paleo there is more to it than just diet - and the exercise component is inextricably bound with the dietary one. But I am not covering that here. All I will say is that when I stopped doing all these things, I did not start losing muscle mass. I got leaner, but I stayed as strong as before. Would it make evolutionary sense for temporary food scarcity or a failed hunt to lead to muscle wastage? We need our strength if the next hunt is to be successful.
Once you've beaten one of the bad guys, it's time to pick off another. My other half found bread to be the next biggest winner - giving up that corrected several annoying ailments she had been carrying around for years. But it's your choice.
How much fruit should I eat? Can I eat honey? Is it possible to eat too much veg?
If you've got to this point, fantastic. It means you've pretty much cracked it. The answers to these and other questions can be found in the many great sites and great books on the subject - there are too many to list here, but I will mention Mark's Daily Apple as one of the best websites on the subject and Mike and Mary Eades' The Protein Power Lifeplan as one of the best books.
If you are successful then one day you'll realise there's no turning back. You'll realise that you know too much and you couldn't go back to eating the other stuff without caring. You will mourn the care-free chip-munching sessions in front of the TV. It's actually rather sad, in the same way as when you realise your childhood is over; but it will be replaced by an enduring satisfaction about the myriad benefits those sacrifices have engendered.