Everything you get will help you get to 1000, so just do what is fun. Campaign and patrol spaces are fine. You might be able to boost a little faster jumping into public events with higher level players. Once you hit 1000, blue drops will stop helping, so then you need to follow the formula more. All you need to do is damage something in an event to get a completion if people around you do it.
Don't bother to infuse anything at lower levels, it costs too much and you don't need to. Your actual equipped power level doesn't matter all that much. If you get a higher level drop and don't want to use it, just keep it in your inventory. Drops will go by your max possible power level anyway.
Keep anything purple/legendary you get for now, you can ditch anything blue or green once you get something higher level.
As you get higher, you'll see more and more quests in your inventory (probably a ton). You can look those up on youtube and see what they give you vs how easy they are to do.
The game is huge, but you can't do too much harm at lower levels so just have fun. My big problem with the game early on is it isn't obvious what is an easy, solo activity or not.
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