Gravity isn’t easy, but it’s the law.
Unknown
Getting In
As you approach the hammock you should be aware of how far it is from the ground and acutely aware of how stable the two connections at either side are. If any of these factors is questionable, stop immediately and take care of it. Test it. Give it a tug or two.
Is there anything on the ground which would be sticking you in the back? Or hurt like heck if you landed on it? Please try to practice the ethos of “Leave no trace,” but I have been known to bend a few weeds over, and move branches and twigs out of the way.
You MAY notice that it is difficult to determine exactly where the center stripe of the hammock is, as that is where you should be planning to gently sit. Many weavers help out here by making the edge colors the same as a central stripe in the hammock. This factoid will make it easier to determine where to sit when you are ready – but not yet!
Lean across the hammock and grasp the other side, the Far Side as Gary Larson would say. Lift it up over your head. This is like putting on your crash helmet, as you will want the hammock to completely protect you, and your gray matter.
Pirouette gracefully 180 degrees, so that you are now facing away from the hammock. Look around. Is this the view you want? Are you facing into the sun? Remember, like arguments, there are two sides to any hammock, and possibly the other is best.
If this IS the direction you want to be facing (and please remember you are STILL holding the far edge above your head) reach down with the other hand and spread out the hammock, locating that center stripe target for the buttocks, and GENTLY sit down, making sure that the back side of the hammock comes up your back and protects your head when you…
Lean back. Adjust. Ditch shoes and pop feet in. Congratulations.
Did you feel the hammock sag a bit with your weight? It should have. Did you feel either end slip or tug or (gulp) make a creak or cracking sound? If so, consider the strength of the branch, tree, or anchor and whether it will be there for you when you really need it. Don’t let it let you down.
And if you thought that was complex, I will note that it is easier than riding a bicycle and quickly becomes as natural.

Getting Out
This is another matter, as you are basically reclining in a bucket of string.
Start by yanking out all pillows below your waist. The lumbar pillow will actually help you roll out. Stick out your feet and bring the front edge of the hammock behind your knees. You will be preparing to gently eject forward, in a rolling somersault. Do not, however, move so swiftly that you dive into the ground.
You can use your hands beside your body, the further back the better, pushing forward at the same time that you push yourself forward, rocking your body so that the center of gravity moves out and over the front edge of the hammock. I have been known to rock a few times to generate the momentum to do all of this. Ah-one and ah-two and woohoo!
As you move forward, you will reach the point where your center of gravity slips over that forward edge. I usually try to locate and slip on my shoes at this point, but that may only really be required for sticky parking lots. Please note that slip-on shoes are the default for hammock aficionados.
Finally, as you move forward to a standing position, it is often handy to grasp the front edge of the hammock with both hands behind you, as a sort of stringy safety handle, steadying yourself as you stand.
That wasn’t too bad, was it? Again, with practice it all comes naturally, although it does help to explain why when I get into a hammock, one of the more annoying elements in the universe is having to get out again because you forgot something. For me it is usually a book, a drink, or the durn cellphone. Arrange accordingly, going through a checklist, before you jump in.

I admit to being surprised that it was that complicated to explain, but when you see the hammock videos with folks jumping in, or doing a belly flop and then rolling over (a legitimate strategy but somewhat undignified) it makes sense to describe it carefully.
I have suggested to my wife that at some point I am going to install a small winch directly in front of the hammock so that I can easily raise and lower myself without all of this lunging. I am afraid that when I reach that stage, she will take her quilting shears to every hammock I own. Always exercise caution around women with sharp implements!