Okay. So a few suggestions.
1) Before you go to PLAY in your local FNM, go there to scout things out. If you have more than one LGS, scout around and see where the most welcoming environment is. Some FNMs are SUPER competitive and will be populated with tons of Tier 1 decks that, well, to be honest, you need either a really polished home-brew or another tier 1 deck to even win any games. Others are filled mostly with players who are working within their budgets, home-brewing and such, and really who are just about having a good time. This is the type of environment to aim for, as a newer player you're likely going to lose quite a bit to get started but winning a few games here or there can make it worthwhile (against the super competitive folks, well, it's just not going to happen and you might get turned off from the game).
2) You're sitting on a single Archangel of Thune. This is a great card, hence why it's sitting at almost $20, but as an individual card, it really won't do much. It's powerful, but it's entirely possible that you can come up with another build and then use the Archangel as trade bait to get the majority of the other cards you need for the build. So keep that in mind rather than just limiting yourself to the cards you currently have.
3) Feel free to tinker around with builds and playtest before you buy the cards. You can do this by proxying cards. The easiest way to do this (without ruining any cards) is to use card sleeves (which you'll likely want at some point anyway). This can be achieved by simply taking scrap paper, writing down what the card is supposed to be, and slipping that paper into the card sleeve in front of just whatever card you want to put in there. So for example, let's say you want to test with Garruk, Caller of Beasts in your build but don't want to drop the $20 per to pick them up. Just build as much of the deck as you can and then put in some Swamps with the paper in front to playtest. This way you can see about building a deck that fits your strategy and that you enjoy before you drop the cash.
4) Ask people for their input and don't be afraid to net-deck to some degree. We'll give you as much guidance on here as possible, but others in your local meta will be more familiar with what you're likely going to run into. Further, don't be afraid to look at what the pros are playing. The argument here is simple, they've put in the time, money, and expertise to build these decks and see how they perform. You don't necessarily have to take their builds card-for-card, but it's really pointless to reinvent the wheel if someone else has already done the leg-work to optimize the deck for you.
5) As for the specifics of deckbuilding, you've actually managed to put more than enough land in the deck (which is a good thing, as most people will typically short the lands in the deck), but you want to build decks that emphasize consistency. You can get a deck to perform consistently by adopting a single strategy and sticking to it and then using multiples of the cards for the strategy, as opposed to having 1-off cards that you're unlikely to draw game-after-game. So, for instance, you have 1x Soldier of the Pantheon, but that means you have a relatively low chance of drawing it in each game... but if you were to have 4x of them, your odds are obviously better. Cards that are essential to your strategy should be 4x or 3x at the least, and cards that aren't necessary by any means but would certainly help, those are 1x or 2x and only if you have extra room.
So... to your specific deck...
I would imagine your best bet will be to build a Boros Heroic Deck as it will likely fit in your budget (or be pretty cheap to piece together) and it should have at least some success. To this end, you'll be building in a bunch of aggressive creatures, mostly in white, and some triggers to help you set off Heroic, pumping your guys and such.
So, the cards to focus on:
Soldier of the Pantheon - he's just good, so as many as you can get is a plus
Akroan Crusader - for heroic, he's going to make more guys... that's a plus
Precinct Captain - he's a solid 2/2 with first strike (all of which is good), but he can also make more guys for ya if he does unblocked
Phalanx Leader - this guy is easily the BEST heroic trigger in your colors - he will give you an Archangel of Thune pump effect every time you target him
Anax and Cymede - another solid heroic target for you to aim for - they'll pump your guys AND give them trample... nevermind that a 3/2 first strike is a brick wall against a LOT of opposing creatures
Spear of Heliod - this is a solid option for pumping your guys - it gives you a source of spot removal while you're at it. If you're in a pinch, you can get Path of Bravery and use it but keep in mind that some games you won't be able to have your life high enough to actually get the boost.
Chained to the Rocks - this is easily the best removal option available in the boros colors... if you can manage 4x of them that is a plus
Assemble the Legion - this will likely be a SB card for you, but you could also just as easily run 2x in the mainboard as this is among the best cards in the format in terms of creating inevitability. Simply put, without enchantment removal (which a lot of decks don't really run), it will just win games.
You're already sitting on a lot of the major stuff you're after in here, namely: Firefist Striker, Imposing Sovereign, Wojek Halberdiers, Daring Skyjek, Fabled Hero - these are all solid options to fill in the build.
As for heroic triggers, you will want to run Gods Willing, Dragon Mantle, Madcap Skills, Coordinated Assault, Titan's Strength, and things of that nature.
So anyway, I hope some of this info helps... it's a bit of a learning curve and if need be I can give you a rough build with more specific counts here in a few days. Good luck and remember that the most important part is to HAVE FUN! The rest isn't really all that important.