Where to mine
Where we conduct our mining op depends on several factors:
What do we want to mine;
What sec status level we are willing to risk;
Where we are going to refine;
Where we are going to sell the minerals/manufacture from the minerals;
What's convenient for those participating.
If I'm running a Tank Fleet of Procurers, meaning I'll mine in .5 - .7, I prefer Amarr space as the belts will have Kernite, and with Scordite and Pyroxeres, I'll have five of the seven basic building minerals. In .8 - 1.0, the Faction space doesn't much matter.
As to refining, post-Crius this will be simple - I'll keep a small POS and a refining array in the Orca and refine wherever. Until then, I'll keep refining in those stations where I have perfect refine standings.
What to mine
The type of ore you can mine in a system varies according to the Faction in control of a region and the security status of a system. You can find a detailed location breakdown and a guide to what minerals different ores yield here:
Information about ores and minerals
If you want an idea of the current value of different ores, you can get that here:
Cerlestes.de Ore Table
Generally speaking, Pyroxeres and Scordite are fine for highsec mining, meaning you do not need to mine in security systems lower than .8, which in turn means you can field a Yield Fleet that sacrifices some tank for greater yield. However, the asteroids in lower security space tend to be larger, which is a good thing for miners. In the end, you have to weigh the balance between yield and risk.
When to mine
The prime time to mine is immediately after downtime on Tuesday, Wednesday, Thursday, Saturday and Sunday. Avoid Monday and Friday after downtime as the spawns on these days result in asteroids smaller than the other days - substantially smaller. As a result, the absolutely worst time to mine is immediately prior to downtime on Tuesdays and Saturdays - still small asteroids but by now the belts have been worked by miners who don't care that they're smaller. To adjust for the smaller spawns on Monday and Friday, I spend some extra time on those two days mining before downtime and after downtime do something else instead of mining the belts.
How to mine (Edited on June 12, 2014, in light of Kronos)
[EDIT: What follows below was posted just prior to the release of Kronos. I should have waited. Kronos was a major buff to the Yield (Hulk)/Fleet. The only bookmarks I need now are a safe spot rally point and I make one for the station I use (I have a folder with these for the various systems I mine and keep that folder open). The new range of the Hulk's Strip Miners (32km) coupled with the new range of the Survey Scanner II (38km) makes being picky about the warp-in unnecessary - if you're maxed, you'll have access to the entire highsec belt from the defaul warp-in point. While I used to mine primarily from various Overview profiles, I can easily do it now from the Survey Scanner results. I'll leave the material below as it was presented for folks who might not be maxed yet and still have a range handicap.]
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Do your homework. Pick a system or a couple of systems that fit with the decisions you've made with respect to the topics above, and before the op create a set of bookmarks for each system - at least one safe spot rally point and one prime mining point per belt.
What is a prime mining point? Asteroid belts are essentially horseshoe shaped. If your fleet is boosted by a well skilled Orca pilot with T2 Mining Foreman links and the mining mindlink, your strip miners will have a range of 25 kilometers. If you position your miners roughly in the middle of the belt, you should be able to reach both the left and right extremes of the horseshoe, as I've tried to demonstrate in the image below.
So, to create a belt bookmark I warp to the belt, usually in a Cheetah, and jockey the ship until I can tell that all of the ore is within 25 kilometers of my ship. This may not always be possible as some horseshoes are too large, but you want to get as many asteroids into the 25 kilometer range as possible. Most belts will comply. Those that won't, you'll have to decide if it's worth the fleet's time to chase those final asteroids down after you've mined the bulk of the belt. Mobile Tractor Units have made it much easier for Yield Fleets of Hulks to spread out at the final stages of mining a belt and get those harder to reach asteroids, which might be divided on the left and right edges of the horseshoe, jet can the ore, then have the Orca pull it in using a MTU.
If you've seen the screenshots I posted previously, you'll see that the UI windows I use leave very little space view. If you need a quick view of space you have two choices: CTRL-F9 will completely clear your UI or, as I prefer and did to take the screenshot above, simply hit TAB and all your windows will collapse. Hit TAB again and they'll expand to their prior state.
I prefer to haul in a very easy manner - with a freighter on the field (I use a Charon). Miners transfer their ore to the Orca's Fleet Hangar and the ore is then transferred from the Orca's Fleet Hangar to the freighter. All just drag and drop with no jet cans. There are altervatives, such as using a second Orca to haul, which has many advantages, such as the ability to use more boosting modules or a tractor unit, they tank better than a freighter and cost less. Downside is they hold less ore than the freighter so you end up warping to station or POS more often.
Another alternative is use a Miasmos, the Gallente ore hauler, instead of a freighter or a second Orca. Much more warping, but the price is right. Some folks just use the single boosting field Orca and warp to station or POS when all holds are full. This isn't a bad solution, but when you position your fleet like I do they tend to be more than 15 kilometers from the asteroids, which means when the Orca is in warp and boosts are down, they won't be pulling ore. By the way, if you're seriously into mining drones, this range from the asteroids that I prefer is also a detriment, making mining drones basically unfeasible due to your distance from the asteroids.