1) In order to get infinite GOLD you'll need to have access to the war table operation specifically geared toward earning more Gold. Josephine is generally the best person to help you carry out the scheme. Basically you have her start the mission since it takes her a shorter amount of time to complete the task than Leliana and Cullen.
2) Once the mission has begun you will need to change the time setting on your PC/Console. By doing so you will manipulate the timer of all war table operations that are active at the time. This can prove to be more tedious on consoles where you have to exit the game completely at times to access date/time settings. On PC make sure your display is set to "Windowed/Fullscreen Windowed" in order to make the process more seamless when using the ALT+TAB key command to switch screens.
3) Once the date/time settings have been set forward go back to the war table and accept the reward. Repeat as many times as you want. The clock setting will affect any existing war table operations that have been started/activated before the clock was set forward so if you set it back to normal before starting anymore you won't have to worry about messing up your game.
GAMER TIP: It is helpful to also set Leliana and Cullen on resource gathering missions at the same time so you're earning resources as well as gold.
INFINITE INFLUENCE AND POWER
1) Reach Skyhold by completing "In Your Heart Shall Burn"
2) Claim a Keep for the Inquisition - The easiest Keep to claim is in Crestwood as it is a part of the "Here Lies the Abyss" Questline. After speaking with Varric in Skyhold you are asked to meet Hawke in Crestwood. Once you go to Crestwood begin the "Stillwaters" side quest by talking to Crestwoods mayor. One of your first tasks is to clear bandits from a stonghold. After you defeat them you can claim the fort as a Keep for the inquisition.
3) Complete "Price of Power" operation at the War Table. Doesn't really matter who you choose to throw at this one just start the operation ASAP. (You can use the time jump method detailed in the Infinite Gold section above to speed up the process if you want to)
4) Leave Skyhold and return.
5) Speak with Farris and begin shopping
6) Buy as much influence as you can afford
7) Without exiting the shop, sell back all of the influence you've bought. This can be repeated as many times as you want before exiting the store. Repeat at your leisure.
GAMER TIP: Increasing your influence will greatly increase the amount of power you have as you earn power for every purchased influence package. Though you'll have access to quest lines you would have had to wait longer to access before you may want to still level up more before completing them.