Helldivers

Use your map repeatedly to watch out for patrols (little red circles) - avoid them, or if you can't avoid them, then do your best to bring the big guy down immediately. If you're fast enough they won't hit the alert, and you'll have a hassle free time.

Early on the chaingun turret seems like it's invaluable for defending locations, just watch out for the indiscriminate targeting - if something is on the other side of you and it, hit the deck before it shoots you up.

You can find any difficulty of planet regardless of which sector you go for, so if you're hunting for unlocks check what each planet in each sector has first. If you're just going for xp you can mash the daily event a bit for double.

Generally speaking one of your strategems should be a one-time-use weapon, pop it at the start of the map to increase the number of weapons you've got on you.