1. General landscapes.
3. General flora and fauna
So, my general rule is, if you're not outside in the heat, the bugs and all that nature offers, you won't get the photos you hope to. Shots like the flying osprey (opposite) aren't captured sitting in front of my laptop. My rule is to try and capture one picture that I like once a day. Obviously our lives are busy and priorities must and all that, but without impinging on your responsibilities in life, try and get out as opposed to thinking that getting out won't be worth the effort.
(i). Use the best lens you can afford for the purpose. For landscape, this means generally wide angle, with higher quality optics than are found in the basic kit-lens level . If you want to make landscapes your priority, consider spending a bit more scratch and getting at least a Canon 17-40 mm L series, which is sub-$1000 and not outrageously expensive in the lens world. For birds, I use the Canon 100-400mm zoom. Used properly, this lens gives amazing results. When I was researching this lens, I read some comments that the review had bought a "soft copy" and was upset. Further research almost always reveals user error. I can take stunning shots and horrible soft shots in the same morning with this lens. Not because of the lens, but because of the mechanics of telephoto zoom lenses. Tripods are a must to prevent minute shake, otherwise you'll end up relying on the image stabilizer and wide apertures to get faster shutter speeds to compensate. The result will be less pleasant images. Big lenses are really hard to hold still to get sharp images of birds at tree tops, so a solid, solid tripod is a must.
For general flora and fauna, I stay within the 24-105 mm focal range, with a macro lens handy for those amazing close ups of flowers and insects. Again, with macro work, a mono pod or tripod is key. Stable platforms = clear images. When you try to skimp on using a tripod, you try to increase shutter speed to avoid blur by increasing the ISO (and increasing your digital noise and distortion) and opening the aperture too wide, changing depth of fields in unwelcome ways.
(ii). Dawn and dusk. If you want those beautiful photos that seem to have that intangible quality, you really need to head out at dawn and dusk. The summer light for me between say 09:00 am to 7:00 pm is just too harsh, too bright. That isn't to say that you can't get keeper shots at high noon. Its just my experience that my best shots are caught at the soft edges of dusk and dawn. Birds are out, and my best bird shots are always at dusk and dawn. Even grass and leaves look better bejeweled with dew.
(iii). Consider filters. I use a wide array of filters. These include filters to pick up different color in the ambient light out there (http://www.singh-ray.com/goldnblue.html). I often stack filters, using a Singh Ray Blu n' Gold at the base of the stack in a Cokin P sized filter, with a Singh Ray Color Intensifier and followed by a Singh Ray Graduated Neutral Density Filter (half clear, half dark to block out the bright sun, with the neutral density reducing the amount of light coming into the camera without changing the color of the light). This effect of using multiple filters in landscape work can have very pleasing results.
(iv). Tripods! If you can use a tripod, you'll generally get much clearer shots. Especially at dusk and dawn, the prime shooting times, light is lower and the temptation to use higher ISO levels and wide apertures will adversely affect your shot. Too low a shutter speed, and you lose sharpness to hand-held blur. If you try to compensate with a super wide aperture, you may have enough light for a hand held shot, but the wide aperture may give a very shallow depth of field, which is anathema to wide-vista landscape shots. Use a tripod, meter the scene in various areas, and if you have to shoot a t 1/3rd of a second at f/18 and at an ISO of 100 for lots of nice, creamy detail in RAW, then you can. Image stabilization just doesn't do it all the time.
When shooting birds with big, long lenses, you need a tripod. Without argument. The tripod allows you to properly steady the lens since your bird will often be a speck in your frame, even out to 400 mm. You can't hold a lens steady to avoid blur at that range. Think you can?
Try holding a laser pointer aimed at a wall 6 inches from you. The laser dot looks pretty stable. This is you shooting hand held at a close subject using a short focal length lens.
Try holding that laser dot fixed at 100 meters now. What happens to the steadiest of hands? The laser dot is jumping all over the place. Similarly, when you try and hand hold a long lens that's stretched out to its max focal length to capture a distant bird or fox, the lens shake at your hand of millimeters translates into much greater shake at the distance of your subject, just like that laser dot jumping around at 100 meters. So use a tripod! And if you have the luxury with a still animal like a great blue heron, use the live view feature of your camera to get perfect focus, then shut off the auto focus, shut off the live view and snap the picture.
Not to flog a product, and I receive nothing from the company in exchange for this this, but I have made the ultimate tripod commitment and went with Really Right Stuff (http://reallyrightstuff.com/Index.aspx?code=46&key=fr). They are an all-American company, with all of their product, "down to the tiniest screw" as they say, made in the USA. You can always reach a customer service rep there by phone or e-mail, with outstanding results. There are definately less expensive options out there, but I cringe when I have students come out with me using $70.00 tripods with maybe a 8-10 lb load rating, using their $2000 DSLR and commensurately expensive lenses. Like putting tires guaranteed to blow out at load on a $100,000 Lamborghini.
But let me say this, with emphasis; When you buy from RRS, you only pay once!
Let me explain; I have a DSLR and expensive 100-400 mm Canon lens that ride on my RRS ball head and tripod set up. When I'm in the field trying to get the perfect bird shot, I carry my camera on my tripod, extended, so I'm ready to shoot supported (critical with long lenses) at a second's notice, which is all the birds, foxes, and other critters give you. Once I'm done and its back to camp, I'll pack the tripod and camera away in my camera knapsack. The point it is, RRS can guarantee that if I properly set up and regularly check my tripod, I can carry my camera over my shoulder all day in complete confidence. My last monopod head disconnected without warning from the body of the monopod when the cheap brass connector screw just sheared off without warning. If that happens on safari or on a trip, you're out your expensive camera and lens while traveling on a long-planned, expensive trip where you plan to take a lot of photos. Imagine.
So, I chose to pay once for a lifetime tripod and ball head setup, get excellent customer service and then proceed to work the shit out of my tripod in the field, in rain, snow, heat and hills, without one scintilla of concern that my tripod will let me down.
Use the best lens for the task that you can afford. Get out early (I mean crack of dawn!) or at dusk for the really amazing light. Try to use filters on your landscape work, experimenting with the less expensive options on EBay before moving to the more expensive pro-grades like Lee and Singh Ray. Finally, use a tripod as often as you can. I also have a Really Right Stuff monopod for my long lens when birding, on days that I don't feel like lugging the full monty tripod when its brutally hot and humid. Any support--like a monopod--is better than no support. Tripod is best however. And as often as possible You'll be surprised.
And get out there! You don't get good shots sitting in front of the television!
Best of luck, I welcome questions and dialogue comments on this blog.