You'll have to take my word for it, because I haven't posted any pix for a few reasons, but I've been a professional outdoor photographer for over 30 years, selling my work to outdoor magazines. I've sold well over 1,000 images, including a few covers. This doesn't pay very well, and because of that there has never been a time when I could afford $18,000 to $22,000 for a really long F2.8 lens, so I have compensated by getting close enough to fill frame with a 200mm, and at times, even a 55mm. To do this, I have relied on almost 50 years of hunting and fishing experience.
The reason I'm starting this thread is to give something back to this site, because even though I've only been around here for about a week, I've found it very informative and friendly, and I'm sure the majority of you can't afford to pay more for a lens than for your car as well. Besides, even if you shoot lenses longer than 200mm, which it appears many of you do, getting close is still very important.
The best ways to do this differs, depending upon species. Just as with hunting, especially bow hunting, the more you know about the particular species, the better you are able to get close without being detected, so if you have questions, be species specific. There are a lot of tricks to it.
A lifelong interest in hunting (I'm actually something of an expert and have also worked as a hunting and fishing guide) has given me a wealth of experience and insights about getting close that I realize I probably couldn't have achieved by photography alone.
Though I also like to photograph backyard birds and such, what I'm talking about is animals and birds in the wilds. That's the part that is really fun and challenging. In fact, I rarely hunt any more and enjoy capturing them on a sensor more than for the table.