Understanding The Mission Grind In EVE Online
The most typical grind is to run missions to get standings high enough to run level 4 missions for a particular corporation, and then to farm that corporation's level four missions for valuable rewards. Level 4 missions are the highest level of mission that can be run effectively by a single character and still be profitable given the time spent. Though level 5 missions exist, they are designed to be run by several people at once, reducing each person's share of loot to the point where they would usually be better off running level 4 missions.
Why Grind Missions?
Pilots grind missions to increase their standings, to get mission rewards, to accrue loyalty points that may be spent at that corporation's loyalty point store, to pick up loot and salvage wrecks during the course of the missions, and to gain access to perks that come with high corporation or faction standings. Also, special bonuses are sometimes possible within higher-level missions. These take the form of extra acceleration gate that can only be entered if a semi-expensive item is expended. In such cases, the room usually contains a valuable bonus of some kind.
In order to run missions for an agent, you must have high enough standings with that agent. The higher that agent's level and quality level, the higher your standings need to be. Getting these standings is the basis of the grind.
The Traditional Grind
Whenever you kill an NPC, your standings decrease to that NPC's corporation and faction, and increase among that faction's enemies. For example, if you kill an NPC belonging to the angel cartel, your standings to the Angel Cartel will lower, but standings with the Minmatar Rebublic will raise. There may also be secondary benefits. Allies of the Minmatar Republic will improve their standings, though to a lesser extent, and enemies of the Minmatar Republic may decrease their standings to you, though this will also be to a lesser extent.
A more rapid change in corporate standings will occur if missions are run for a corporation. These missions will typically also involve shooting the enemies of the corporation issuing the mission, further improving your standings gains as you run them.
Every sixteen missions that you run, a storyline mission will be offered by a random agent belonging to that faction. When completed, that mission will drastically improve your standing with the corporation that offered the mission, but also significantly increasing your faction standing. For this reason, storyline missions are the most important part of grinding missions for standing.
Agent Standings Versus Corporate Standings Versus Faction Standings
As you run missions for an agent, your standings with him in particular will improve fairly quickly. Your standings to that agent's corporation will also improve, though at a much slower rate. Finally, when you run storyline missions, your standings with the faction to which that agent belongs will improve.
If your faction standings are higher than your corporate standings, they will be used to see if that agent is willing to talk to you. Because faction standings affect so many more agents, they are more desirable.
To be absolutely clear: Agent standings are with a single agent, e.g. Karde Romu, and improve as you run missions for that agent. Corporate standings are with a specific NPC corporation, e.g. Ministry of Internal Order, and change as you run missions for any agents in that corporation. Faction standings are with the larger NPC factions, e.g. Amarr, within which are many corporations, and change slightly as you run missions in general, but change dramatically as you run storyline missions.
Perks of High Standings
Once you have access to level 4 missions, there are still many reasons to grind standings. Here are a list of perks that can be gained with high standings to a corporation or faction.
Jump Clones: Once your standings with a corporation reach 8.0 with a corporation or faction, you can install jump clones in their stations. Though there are workarounds involving null-sec stations, most players will not have access to that option, and so standings are required. Jump clones are basically spare bodies that you can leave in a particular station, and jump into, once every 24 hours. This saves a ton of travel time, and can also be a way to keep implants safe, as implants will remain in inactive clones, risk-free. These are a must-have for most serious EVE pilots.
Free Refining: Whenever you reprocess ore or goods in an NPC station, a portion of the product is taken by the corporation that controls that station. Once your corporate standing with a station's controller is 6.67 or higher, you no longer lose product in this way. Note that you may still lose product to waste, depending on what your skills are and what you are reprocessing.
Reduced Transaction Taxes: Normally, when you put up a sell order, you must pay a tax to the controlling corporation of the station in which you reside, as well as a tax to the faction of which that corporation is a member. You must pay this tax as well as an additional a broker fee when putting up buy orders, as well. Though the Accouning and Broker Relations skills will reduce these costs significantly, even when trained to level V you will still pay a 1.25% tax on sell orders and .75% tax on buy orders. The higher your standings with the owner of a station, however, the less of these taxes you will pay. Though these small percentages might not seem like much, if you are making money on market manipulation or volume trading they will quickly add up.
Locator Agents: These special agents will reveal the location of any pilot in EVE, though the speed with which they respond will vary depending on the level of the agent. What standings are required for this depends on what level locator agents are available with a specific corporation. Though locator agents exist for every level, the lower levels aren't very helpful because they are only able to find targets within the region where they reside. Locator agents must be level 3 in order to find targets located anywhere within EVE.
R&D Agents: R&D agents are a lucrative and specialized enough field that I could probably write an entire article about them, but this should give you the basic idea. Research and development agents are special agents that produce lucrative datacores for you, on a daily basis, without you actually having to log in or do anything. These agents are one of the best sources of passive income in the game. As of this writing, datacores still accumulate even when the character using them is unsubscribed. Because not all corporations have R&D agents, it is in your interests to ensure that you are running agents for a corporation that does. In order to use a datacore agent to produce datacores of a given type, you need to have the skill relating to that datacore trained to a certain level. For example, in order to use an agent to produce Caldari Starship Engineering datacores, you need to have the Caldari Starship Engineering skill trained up. The higher the agent level, the higher your skill must be trained. The Research Project Management skill allows you to use an additional R&D agent per level. Any account that does not have five R&D accounts churning out datacores, is wasted ISK.
The grind isn't that bad, and the perks are numerous. I hope this made things a little more clear for all you newer players out there. Now get out there and grind until you are filthy rich.