Like i said, go to bulbapedia.net and make a well rounded team
To be honest, g/s is not all that challenging and you can literally defeat elite 4 or other players with similar version easily with just your starter. The challenge comes in at pearl and on, then, you really need a good team of pokemon to actually win.
i never really 'learnt' pokemon i just sort of played it and learnt as i went along, althought back when we and my mates were 6 it was all we did i have such good memories with that game.
OBviously relying on Metronome solely will not work, but it's an added bonus to having alongside Togetic's other abilities it can learn
When my Crystal game still worked (damn cartridge stopped saving on me some years ago) I had Typhlosion with Thunderpunch and Earthquake. Sure, based on STAB these abilities are not as strong as with other pokemon, but having these two abilities are what made me like Typhlosion so much. I wrecked a good majority of the Elite four and Trainer Red's pokemon with the move set I listed on the first page. It doesn't always have to be about min/max--everyone plays the game differently anyways.
as a side note, Typhlosion is the best starter OP, but if you like a challenge, keep playing with your Feraligatr
There is nothing special about Togetic. You can just as well use Noctowl which you can acquire at the start of the game. Noctowl boasts superior defensive spread, is faster while having roughly the same offensive stats. The only reason you'd use a Togetic over a Noctowl is if you like Togetic better; or if you want to use TM's to teach it Fire Blast, Shadow Ball or Zap Cannon. But Fire Blast is almost always better on a Fire-type due to STAB, Shadow Ball offers close-to no synergy with Normal/Flying and Zap Cannon only has 50% accuracy.
Also Murkrow is squishy as hell and its movepool is abysmal, without BW Prankster or its future evolution Honchkrow it can't due much. Sure you can use it as a glass cannon, but its movepool is horrible and lacks coverage.
Good Flying-types are scarce in GSC, the better ones are Xatu and Crobat.
Lapras with Ice Beam managed to solo Lance for me, thats all i remember.