I find GCIII not to be a game for the faint of heart

It is more involving then many other games I have played.

If you are going to play it play it for a few hours straight. If you want a casual game  with less thought then Master of Orion would due

An update. I played on biggest map. Expanded around a little bit and then bam! Found the Yor and one other race and in terms of power I am nothing compared to them. This is what really stumped me playing gal civ 2 and now 3 where the AI seems to beat me whereas in games like Civ, I do get some ways to hold off the AI or at least be ahead of them by focusing on research. Seems like my research isn't enough. 

I played GC2 for long and would say I became a routined player. Still learning GC3 myself.

FWIW, some points: having negative income early on in GC3 is normal. Playing the Iridium helps, but of course they have other downsides.

Progress on a certain map depends to a good degree on the specifc layout - many/good quality planets nearby make everything way easier.

Dunno what the expert players do, but I do usually start getting 1-2 speed techs (faster ships help colonizing), then universal translator, the first diplo tech, and then focussing manufacturing/research stuff in the early turns.

I do some custom designs for cheap colonizer ships, cheap small constructors etc. so that I only build the more expensive versions of those when they have something I really need (usually: longer range).

Don't mess with the wheel you will lose production in the long run. That is my new strategy with the latest update. Otherwise I might would considering doing away with money since rush buying is so expensive anyways.

I try to get three shipyards right away. I won't let my worlds finish developing to get these. One for building colony ships, constructors for resources, and constructrs for eco nomic starbases. You could wait to get three constructors when you select it in ideology. I try to get the missionary and preparedness centers in ideology. I wouldn't worry about declaring war ideologies until after about turn 120 on insane maps. I wouldn't bother with war strategies until someone major is hostile towards me. Ideology point buildings are the last structures I build on colonies.

 On my homeworld I would make it a manufacturing world. If you have other worlds within six hexes from the shipyard I would do it to them. I would move the three shipyards to do this. Don't build shipyard on planet instead build constructors. Make to build duranthium refineries their worth having on manufacturing worlds. I would set auto upgrades off on these worlds, otherwise they will be building factories when you need stuff like duranthium refineries. 

I would research diplomatic translators first, because on most manufacturing worlds you we will want to destroy resources. Sell them first. Remember most deals the AI makes with you they will try to rip you off, so renovate deals. This is not always the case with technologies. When you sell stuff remember different ais sell stuff at different prices, so you should check with everyone. When they ask for stuff it helps to appease them once then stop. It's best to do this when they are asking for less than 300 credits. Do not pay tribute. 

 As far as starting colony ships only put a colony module on them. You don't have to worry about speed until you meet someone anyhow with as few colonists as possible anyhow. Don't bother rush buying until you find planets that needs colonising without colony ships. If you find you need more range just add life support until you see colony ships. It's a good idea to stop rush buying after you fall below 2000 credits. 

My setting are immense abundant with 40 opponents.

Make sure to at some point build a economic planet. I would recommend buying the mercenary scout. It makes a difference on exploring.

As to the original question, I find it much more immersive to create my own civ with strengths and weaknesses to mirror and mitigate respectively what I consider to be important. I also enjoyed creating the backstory for this civ as to how they came to be a player on the galactic stage.

As to developing your own strategy, I think there is no shame in playing a few games on easy to explore the tech trees and get comfortable with the locations of techs that will really boost your playstyle.

The biggest early game tip that helped me was sharing the starting shipyard between the capital planet and a nearby system of 2-4 habitable planets. Not always possible, but amazingly effective if you can set it up.

I personally don't mess with the wheel, because I'm not good at micromanaging, but that can also be a good way to get a few important techs earlier at the start of the game if you are so inclined.