Tough question. Personally, I have little idea of what cards are from what packs, it'd probably take me an hour or more just to browse through the list of packs and build a list of good cards from each one.
But, some general suggestions…
With a limited sized card pool you're probably looking for a dual faction deck rather than a single faction one. At your level of experience I would not do more than two factions yet as it requires consistently good resourcing decisions that you may not be ready to make.
If you can, I would also pick up a copy of Secrets of Arkham. Lots of good cards in there for all factions.
Personally, I wouldn't worry too much about being competitive right now. You're a beginner, you're going to need to build up some experience for a while.
In general, pairing two human factions can be a little harder for beginners as they tend to feel they lose out on the Terror struggle. So it may be easier to start with Human + Mythos or Mythos + Mythos.
A good rough prototype to start out with is 30 characters, 8 supports, 12 events. Mind your cost curve too, you need some cheap guys that you can afford to play early in the game.
It's less about what specific cards are in your deck and more about knowing why you chose the cards you did and having some sort of plan.
Here's what I suggest. Take all your cards and sort them all out. Go through each faction one at a time, jot down cards that seem to go well together or fit a theme you're interested in trying. After you've done this for all the factions, review your notes. Try to pick out two factions or themes that sound like they might fit well together. These might be themes that are both strong at the same thing (do one thing and do it well) or themes that cover each others weaknesses (make a well-rounded deck). Play some games with that deck. During the games, pay attention to cards that you rarely use and cards that you're always happy to draw. Make some changes - take out the cards that you didn't like and replace them with something else. What is it about the cards you liked? Should you look for more cards similar to those?
After you feel comfortable with this deck and it's working well, write down your list so you can reconstruct it later and move on to another deck, ideally with two different factions than the first. Repeat the same process with the new deck. Then do it again. Every new deck you make will teach you something. After you've had a good taste of each faction and some experience with these first decks then you'll be able to go back around and feel like you know what to do to make the decks stronger. So maybe pull out one of your first deck lists and tune it up with your better understanding of the game you now have. Congratulations, you're walking the path