Obviously casual play is a lot easier to get moving as your deck can be far less consistent and that's okay. But, if you're going for casual play, there really aren't that many suggestions that can be offered as everything will vary tremendously based on how competitive your casual play group is, how good their decks are, the sorts of things they're doing, etc.
The best suggestion I could give with regard to getting more familiar with the game is to try some sealed events first. Sure, they draw on a different skillset than constructed play, but they have three added benefits. First, what is in your collection is irrelevant - everyone has a level playing field depending on what they pull. Second, there is a MAJOR premium on deckbuilding. It might seem simple, but getting the correct 23-24 cards to 17-18 lands to make that ideal 40-41 card deck is quite the challenge. Sealed would not only help you familiarize yourself with the deckbuilding process, but it also puts you in a room with several other players who can help if/when you're struggling. Third, sealed events help you learn about playing strategies (based on what your deck looks like) while also adding to your collection in the process, in turn helping you for constructed events in the future.
To that end, I would suggest trying to find drafts or sealed events at stores nearby and attending those. If you're not comfortable with a draft just yet, just sit in and watch each player and what they're taking. Then observe the deckbuilding process and how the games play out. Ask people if you have questions, but keep in mind that they don't want to disclose their colors/cards during the draft process and then their hands during play (but questions about a particular play they made or something like that after a game is over are often helpful). You can also do draft simulations on sites like Tappedout.net to familiarize yourself with what a draft might look like and how it might play out. Then, once you're comfortable, these will likely be the more rewarding, amusing events - as opposed to trying competitive constructed play, where, I'm sorry to say, you're likely going to lose most, if not all of your games (which isn't much fun).