Doing one of those, normally it's not the selections that are the biggest obstacle, but the patience required to see it through.
Some research would be good, but at odds of 1/10 you should see no real need to devote hours on a single pick. For example, the U5.5 goals you mention, if a team is particularly often involved in games that go over 3.5, then theres a chance they may slip from a 3-1 to a 4-2 or 5-1 against a weaker opponent.
Whereas if you see a team who are very defensive at home, then maybe select them to keep the score down! Some small work and a lot of patience and it could certainly be done.