Apart from design exams which are purely theory in nature, you are going to need a few tools and resources in order to pass your exams.
I speak from experience working on live networks for years and taking many Cisco exams.
1. Good study guide or two.
Most people refer to one main study guide and a backup one for reference. It's rare that one guide covers everything. It should be you will always have authors coming from a different perspective and of course, Cisco has this habit of adding stuff to the exams that isn't in the syllabus.
2. Practise exams.
A must have tool. I've learned through bitter experience that you think you understand a subject but when you see a question about it with five similar answers you realise that you don't know as much as you thought you did. Please don't discover that in the actual exam.
I recommend you take exams from day one, even if you don't understand the subject yet and you only get 10% its part of the learning process.
3. Hands on time.
You simply must get lots of hands on practise for the actual exams because a large part of the exams are the sims. I'm going to estimate around 100 hours for the CCNA and around 250 for the CCNP. The average for the CCIE is 1000.
Use Packet Tracer, GNS3 or your own home rack which you can buy on eBay. I've post a site called CCNA Home Lab to help you work out what to buy.
4. Flash study cards.
These are cards which ask you a question and you click on it to see the answer. The old fashioned way was to write it on a card with the answer on the back. There are several iPhone and Android apps out there with study cards now. It's a great way to cement your knowledge and study while on a train or sitting down waiting somewhere.
5. Cram guide.
A cram is the main learning points per subject written down. Port numbers, commands, show commands and so on. Pure knowledge and much of the exam is taken up testing you on these sort of questions.
6. Video lessons.
I never learned with these, I can't get on with them personally but many students find them very useful. I prefer to learn by doing labs and reading but if you learn better by watching a teacher then CBT videos could be a great help to you.
Hope it helps.