Honestly, it's a bit fuzzy. I don't recall every single detail about my first official journey through Hoenn. This is just the scattered fragments of memory that I have been able to gather so far.
I very clearly remember picking Treecko as my starter. It was my favorite of the three Hoenn starters then, and it remains so to this very day. As for other Pokemon, I caught a Taillow and Wingull to be a part of my team. Then I caught a dozen Wurmples that I never even bothered to raise because of my mentality at the time being "ugh level grinding sux," or something like that.
Being the age of 7-8 and playing the main Pokemon games for the first time, I kind of stumbled through the game, without a single clue as to what I should be doing. (I also kept looking for Shadow Pokemon, but of course, I failed to encounter one.) I caught a Shroomish, an Electrike, and an Aron along the way. When I got stuck trying to beat the third Gym, I spent way too much time running around while Shroomish and Electrike sat in the Day-Care, until I had two Level 35-37 Pokemon(still in their basic stages) that I used to beat Wattson through sheer over-leveling.
I do not recall much after that, except putting Aron in the Day Care as well. Then I got to Winoma. I could not beat her because of that *insert foul word of your choice here* Altaria. Then I pulled Aron out of the Day Care at Level 38, leveled it once to evolve it, and narrowly defeated Winoma. Skipping ahead to the section of the game where Surfing is required to go anywhere, I trained Breeloom, Manectric, and Lairon(soon to be Aggron) while leaving my other Pokemon as they were(yes, that includes Sceptile, who never increased a single level after evolving, for some reason that probably had to do with laziness). I defeated the remaining Gym Leaders, got through all the story events, and made it to Ever Grande City.
Victory Road, the final stretch...and my ultimate downfall. After wandering around the dark maze for hours, fighting off all wild Pokemon and Trainers with my overpowered Level 54 Aggron, I finally got fed up and quit after Aggron fainted. And because I did not know how to internet yet, I had no access to a guide of any sort, and I restarted the game. Yep, that's right, I never finished my first play through.
Now, this may sound a little sad, but it actually helped me learn how to play the game. I learned not to over level one Pokemon and to keep a balanced team. I improved in the puzzle-solving field, allowing me to actually get through Victory Road in my second play through, without the use of a guide. It also had a side effect: it saved the end of the game and the post-game features for another time, thus giving me a reason to play again. And when I did, I decided that I wished to continue playing the Pokemon games. So even though I didn't beat the game on my first adventure, it led to my eventual love for the Pokemon games as a whole. So, I still look back on this adventure fondly!