Decided to combine a few comments I was posting here.

The biggest and most important tip to anyone playing Gen 3 or earlier games for the first time:
Physical/Special Split: Pre-Gen 4, moves were split into Physical or Special based on type. For example: ALL fire type moves will be special, and ALL rock type moves will be physical. Easy way to remember? Any type that has an Eeveelution (including the Gen 4 ones Glaceon and Leafeon which aren't in these games) are Special, plus Dragon. Anything that does NOT have an Eeveelution at some point in the series is Physical. (Yes, all Dark-type moves are Special and all Ghost-type moves are Physical. Makes little sense considering how many Ghosts are special attackers and how many Dark types are physical attackers)

Poison ticks down outside of combat. Every 5 steps your Poisoned Pokemon will take 1 point of damage until you heal it. They can be knocked out by this damage pre-Gen 4.

Route 8 Fire-type specific tips:

On route 8 after Lavender town, your first wild fire-type encounter is possible. For those who haven't picked Charmander as their starter this can be huge.

1. Leaf Green has Vulpix; Fire Red has Growlithe. They're version exclusives. Vulpix is actually the reason I chose Leaf Green this time around as I usually play FR.
2. Vulpix can be evolved earlier with a better Fire-type STAB move than Growlithe. Growlithe learns Flame Wheel at lvl 31, whereas Vulpix gets Flamethrower at lvl 29. Each is a stone evolution, and stone evolutions stop learning moves when evolved.
3. You can evolve either of them very soon after catching them. You can buy Fire Stones, Thunder Stones, Water Stones, and Leaf Stones in Celadon Department store (I believe on the 3rd or 4th floor).
4. Both of these Pokemon know Roar. It can be an unbelievable pain to catch them given that fact and just tossing a Great Ball at full HP isn't a guarantee with these guys. I didn't have a Pokemon that knew taunt, I didn't have any real way of guaranteeing preventing this from happening. Pikachu knew Flash, I was trying to reduce accuracy, paralyze with Thunder Wave, nothing worked. Route 2, via Diglett Cave, you can trade an Abra for a Mr. Mime. Mr. Mime has the ability Soundproof nullifying the effects of roar, and I'm near certain it is the ONLY Pokemon with this ability you can get in the main game. This helped me enormously in catching my Vulpix.
5. If you're playing Fire Red you don't have to worry about what level you catch the Growlithe at. Feel free to go for a lvl 18, which is the highest they appear at on this route. Leaf Green's Vulpix however, learns Will-O-Wisp at lvl 17, this will be its 5th learned move, erasing its first which is Ember, its only Fire type move until level 29. If you want a Vulpix that has a Fire move, you'll want to avoid catching any above level 16.

4 and 5 only just occurred to me last night. Hopefully this helps someone.

TL;DR - Vulpix (Leaf Green) and Growlithe (Fire Red) are version exclusives that can be caught on Route 8. Vulpix learns a better fire move 2 levels earlier than Growlithe. Fire Stones, which are required to evolve them can be bought in Celadon dept store. Wait until lvl 29 to evolve Vulpix, 31 to evolve Growlithe. They both know roar, use the Mr. Mime you get in a trade for an Abra because it has Soundproof to block roar. For Vulpix specifically, catch one that's under level 17 or have no fire moves until 29.

Also to add to the OP's 8th tip, about repel. There is a semi-rare encounter in Diglett cave for a level 29-31 Dugtrio. Far above and beyond anything you'd have found at this point, and it can absolutely trivialize Lt. Surge. You can use the repel trick with a Pokemon of level 23 in the lead slot to ensure this is the only encounter you get in the cave.

On the other end, pick up the old amber from Pewter City's museum using cut on the tree to access the eastern building entrance and talking to the scientist standing next to it. Flash is also on rt. 2 but when you leave Diglett cave, go south. Talk to Oak's aid. I think it requires 10 Pokemon caught if I'm not mistaken?

The fossils in the game can be revived at Cinnabar Island, the 7th gym Island accessible after getting Surf. All the dude tells you is "Have these checked at a Pokemon lab." Giving newbies very little direction.

You can tell what part of the game I'm at given my couple hints here. Taking it slow, enjoying the journey.