1492 is though for Venice. Its basically the same as in 1453 or 1419 except for the fact that their neighbours are bigger, and that venice lost some provinces.
I dont know what to tell you, but one thing is sure - venice does not need slow expansion. It needs some serious FAST expansion. And a BIG fleet too (keep in mind that in-game Veneto is like an island and can be blocked by a fleet!). Personally, i would grab the Alexandria COT at the start if your fleet is bigger then the turkish one. And expand as soon as possible in Italy. Dont let Spain-France get too strong there. If one gets too many provinces in Italy ally with the other to kick em out.
In economical terms - if you manage to get a fleet about 110 ships and if you dont have a portuguese player, i would sack Lisbon to get their maps, and use a fleet composed of 100 ships to go all the way to india to conquer some COTs. Remember that a fleet with 100 ships do not suffer atrition, except for movement atrition. Venice can get pretty strong but it all depends on the players in the other countries because your leaders will generaly suck for the entire game. You must focus on a large economy to make up for that. The COTs and monopolies in Asia can help you in that - as they are a money making company.
Maybe you can even convince Spain to align with you and let you sack Porto's maps (if they are not played) by peacefully accepting their current position in Italy. I doubt Spain will want to go to Asia anyway, since they will be busy with America.
Diplo wise, since Spain will be the strongest power all the way up to 1630, i would ally with them, as far as they contain themselves in Italy. After that i would change my alliance to France to kick the Spaniards for sure from Italy. As for the OE, from a 1492 perspective, i doubt you can be their friends. It isnt that profitable.
Anyway, good luck! If your skills are basically the same as everyone's else, then i fear you are in a very bad position.