Stellaris has a fairly complicated economy and poor choices early on can easily cripple or even ruin your empire later down the road. Influence is one of these elements you need to manage since it’s easy to spend all of it on Frontier Outposts in the very beginning of the game. Unlike minerals or energy credits, Influence can absolutely turn the tide of an empire’s expansion if managed properly. When growing your own faction, it’s important to take advantage of the various opportunities that arise while playing to snatch up as much Influence as you can. This economy is not nearly as fast or steady as the others, so always seek out new ways to increase your pool of political power.
One way to gain Influence is by declaring rivalries against someone, which will increase the amount of Influence gained. You can have up to three rivalries at any one time, but make sure to be strategic with who you declare this against. Creating a rivalry will net you a permanent -100 opinion, but if positioned correctly this can be instantly nullified. If other factions, neutral or friendly, have a rivalry with the same opponent then you will net +25 opinion each from them.
Another way to gain a large amount of Influence is through political mandates. Now this will require you to go the more diplomatic route in Stellaris, but if your empire has an elected ruler then these will pop up from time to time. It’s random what each Presidential Mandate will be, but always try to finish them since they reward a massive amount of Influence upon completion. Each mandate will be based off what said presidential candidate’s background is, so make sure to plan accordingly once a certain leader is elected. Given that the reward is more Influence than an empire can usually generate in a year or even two, these are critically important to your success.
Finally, there are a few smaller ways to help generate Influence, but they won’t be to the degree of say a mandate or possibly several rivalries. Like almost everything else in Stellaris, certain technologies will grant you Influence boosts to your monthly stipend. Make sure to try and research these technologies early on to maximize your incoming amount. This also goes for lowering expenses, but this is more for managing what you actually do with said currency. The last way to obtain Influence is through certain random events or anomalies that occasionally pop up. If you’re hurting for this political currency, try completing a few of these when you have the time.
The key to a successful empire in Stellaris is managing your Influence, so try and get somewhere around +2-3 a month. Sometimes it pays to be frugal when running an entire solar system.