I have been asked several times to detail my Talk-and-Turn method of wildlife approach that I have mentioned in a couple recent posts. Since I teach the method in my seminars I decided I might as well write a brief explanation of it here for those who want to understand it. It has worked for me for over 30 years and it can work for you too, if you have the patience.

Wildlife photography has always been about patience, luck, and more patience. Most wildlife, as opposed to zoo animals, are naturally skittish around humans, they will turn and disappear at first sight most of the time. For this reason alone its very crucial not to startle the animals you are looking to get closer to. Anytime I spot an animal I want to get closer to I immediately start to make my presence known by simply walking back and forth and talking low while still at a considerable distance, making sure NOT to take any steps in their direction. If I am already too close the subject will leave and I am off to the next one. If I am lucky, it will recognize me as a non-threat after awhile and continue on with whatever it was doing, usually foraging for food.
Once the animal has recognized you and decided to stick around, then you can make your approach. This is when you need to set up your tripod, if you are going to use one. The key is to never walk directly towards the subject, nor to walk too far at a time. You don't have to talk about anything in particular, but you need to be almost constantly talking. A higher pitched voice will often irritate the animals, particularly raptors, so if your voice is high-pitched, then try to artificially lower it. The distance you can walk at one time will be relative to the over-all distance that you are from the subject, long distances can mean longer approach lengths. I try to never approach more than 20 yards at a time to start with, shortening that distance with every pause. Walk at an angle so that your approach angle is more than 45 degrees from the subject, meaning more sideways than forward. Walk slowly and keep talking soft and low. Do not look directly at the animal while walking as this can be perceived as a threat, or as a challenge. After your first approach segment, set down your tripod and take a picture, this helps them recognize the shutter sound early. Leave the tripod and turn your back to the animal, still talking, and walk around the spot, staying close to the tripod, but letting the animal see that it is separate from you. After a few minutes, when you are sure you have not bothered it, pick up the tripod and make your next approach segment, this time sideways in the other direction, don't forget to keep talking. Set your tripod down, take a shot, turn your back and mill around some more. If you notice, this is how most wildlife moves around when it is grazing or foraging. Always give them time to get comfortable with your position before moving on. Sometimes this can take 10 or 20 minutes, but learn to judge their nervousness by their responses and actions. I guarantee your will fail this approach method MANY times before you make a successful approach, but that first time will thrill you!
Keep making your slow, zig-zag approach just as above, but remember to make each approach angle a little shorter than the last one. If you are hand-holding and not using a tripod, just lift the camera up and take a shot at every stop, and it doesn't hurt to take shots in other directions too (you can always delete them while you are stopped so you don't fill up a card). The shutter noise is unfamiliar to a wild animal so getting them comfortable with it is critical. You will also have more luck with a group of animals over a solitary animal as they feel safer in a group, especially if you are in an area where there are natural predators around.
Move slowly all the time, especially if raising a camera to your eye as any quick motions will be cause for alarm. Be carful not to trip, even over your own two left feet, as this will scare the subject off pretty much every time! Avoid making unfamiliar motions as you get closer (like changing lenses) as this will also spook many animals since they have not seen or heard those motions and sounds before. Carrying two cameras with different lenses on a double strap is a good technique to use here. (I like to carry 2 bodies, one with a 150-500mm Sigma and one with a Nikon 28-300mm, both with VR).
Whether with or without a tripod, once you start getting closer, and within good photo range, start kneeling down on occasion. This gives the subject an indication that you may be tiring and just wanting to rest for awhile, another safe indicator for them. If there are trees or boulders around, position yourself beside them, but never behind them! Always give the subject a clear view of you when using this method. Hiding, or disappearing from sight is a stalking method and will raise alarm! Take lots of shots when you get within range, vary your exposures, especially your aperture setting to get different DOF in your images.
If you have a day with small clouds going over and blocking the sun on occasion, just wait it out, if the animal is not frightened of you, just be patient. Remember, even when it is not watching you, it is listening to you, it will always be aware of your presence. You have gained its trust, to a certain extent, value that trust and honor it.
Most important of all, once you have made that successful approach, leave in the same manner. Let someone else use the same method, or another one, to also get within that good shooting range.
You can easily spend 2 to 4 hours to get the shot using this method of approach, but it will be WELL worthwhile once you see the shots you can get with it.
Good luck, and I hope this helps some of you who read it, and I hope it isn't too long! ;-)