Strategy.This section is based entirely on my own personal opinions and experience. I am not an expert on Pokémon battling, especially competitively. I am mostly a solo player who occasionally participates in casual battles with friends, so if you're looking for the absolute best strategies on competitive battling, you should probably look somewhere else. This strategy is just what works best for me personally.
The first thing I do is look for a good nature for my Cyndaquil. Cyndaquil, and the rest of it's line, has the most base points in it's Speed stat, though Special Attack comes in as a very close second. Therefore, the best natures, in my humble opinion, would be either Modest or Timid, with the former raising Sp. Attack at the cost of Attack and the latter raising Speed at the cost of Attack. Since my personal strategy is <>pretty much nonexistant> to just pummel my opponents into oblivion, I prefer a Modest nature to boost my Cyndaquil's Sp. Attack power. It will usually strike first against it's foes, but a Timid nature would make sure that it almost always does.
Secondly, the next thing on my to-do list is to check out my Cyndaquil's Ability. It's standard Ability is Blaze, with causes Fire-type moves to do 50% more damage when Cyndaquil's health is below 1/3. It's Hidden Ability is called Flash Fire, and adds 50% damage to Fire-type moves and immunity to Fire-type attack damage and Fire-type Hidden Power damage when hit by a Fire-type move. Personally, I don't think it's very likely that you, or your opponent, will fight Fire-type with Fire-type, so I personally believe that the Blaze ability is the way to go. Please note that everything I've said works well whether you decide to keep your Pokémon as a Cyndaquil, Quilava, or Typhlosion. Strategically, it (unfortunately) doesn't really make sense to keep your Cyndaquil from evolving because it will miss out on stat boosts that will ultimately make it stronger.
Now, since I'm mostly a semi-casual battler, I don't know very much about IV and EV training, even with the introduction of the Super Training addition to your Pokénav in Pokémon X, Y, Omega Ruby, and Alpha Sapphire. I do plan on looking into it more in the future, but I'll keep silent on it for now since I'm kind of an amateur. There are plenty of other resources right now online that are more informative than me on the subject.
Because of my particular hard-hitting battle style, my Typhlosion's moveset would be something like: Eruption, Flamethrower/Hyper Beam, Solar Beam, and Focus Blast. I like my Typhlosion to have maybe one or two heavy-hitting Fire-type moves, but I also like to have a little element of surprise, which is why I also use a Grass-type and Fighting-type move. If I decide not to have two Fire-type moves, then I'll usually go with Hyper Beam, a Normal-type move that hits most Pokémon types relatively hard. Every one of these attacks makes use of my Typhlosion's Sp. Attack boosting Nature, and are a good addition to my power-hitting set-up.