Avoid Traffic - Don't anchor where there will be a lot of traffic, like fishermen or boats returning to a marina. The anchorage sites we've chosen for the Akron Power Squadron "Anchor Outs" will be out of the line of normal traffic.
Swing room - Don't forget, if you have 70' of anchor rode out, you swing at a 140' diameter. Make sure the other boats, who might have similar rode out, won't interfere with your 140'
Look at the boats already anchored. On Lake Erie, if they have a single anchor off the bow, these boats are usually pointed into the wind. Keep in mind that sailboats with keels will not "swing" the same as a power boat - the keel acts as a brake and slows their swinging rate down. That's why, in general, you should anchor closer to a similar boat (power boats next to power boats)
Prevailing Wind - We prefer to select anchorages where the wind will be blocked by land - in other words, anchor north of Kelley's Island when the wind is out of the south.
Holding - pick an area where the bottom has good holding, and make sure you know what the bottom is (sand, mud, grass, etc). See the notes for each anchorage.
Back down to set the anchor - After I let out my anchor, I will back down to "dig in" the anchor into the bottom. I have outboard engines, so I run them pretty hard in reverse to dig in. (If you have higher torque diesels, you might not have to give it as much power.)
Anchor Light - there will be some boat traffic, if only a random fishing boat or another boat coming in to anchor. Make sure you have a fully visible, 360 degree white light showing. The Coast Guard has cited boats at anchor that did not have adequate lights showing - that is, 2 mile visibilty is required.
In the old days, a 12 volt anchor light could draw a lot of power. You may want to purchase a Coast Guard approved, LED anchor light that has a sensor to turn on and off at dusk.
Anchor watch - Once your anchor is set, take several compass bearings on visible landmarks. If your anchor is set, the bearings will change only slightly, as the boat swings with changes in wind direction. If they change significantly, you may be dragging. If you are, and you have the room, try letting out more rode to increase your scope. Otherwise, you may have to re-set your anchor -- usually moving to another location. Check Anchorage notes for good landmarks for bearings.
Most GPS units have an "anchor watch" feature, which will sound an alarm if you drift outside a defined circle.
Second anchor - You might want to set a second anchor if you are in windy conditions. I often set it about 45 degrees from the first anchor, usually taking it out by dinghy.
In our APS Anchor-outs, we don't plan to anchor when the wind is that strong.
Rafting - You can raft with other boats at anchor, but do that at your own risk. First, you'll need lots of fenders, to keep the gelcoats apart.
Waves can cause two rafted boats to collide, even when they seem to be floating safely. If two boats are rafted and a wave comes by - say, from a wake - the first boat will go "up" relative to the second boat. When the wave passes the first hull, it will go "down". At that same instant, the wave reaches the second boat, forcing that hull to go "up". You can see that the relative "up and down" motion between the boats is twice as high as the up and down motion of the single boat.
Warning - if you have your hand between both boats when the waves hit, it could get crunched between the boats.
Rafting at night is generally not a good idea. If the wind picks up, changes direction, or you start dragging anchor, you are tied to the other boat which limits your options.
A Dinghy is a desirable but not required part of anchoring. Use the dinghy to go between boats, or to go ashore.
Water shoes are good footwear in the dinghy. In most cases, you will have to get step of the boat and into the water when you go ashore. Water shoes protect your feet from rocks or uncomfortable stones.