1. The strength of your fleet has little, if anything, to do with how successful you are. While a strong fleet is nice to have, in the early game this can be a massive setback to your economy, with little to no return when attacking active players. In addition, even a small amount of real money can unbalance this even further.
2. Don’t worry about being attacked. As long as you make sure to dismiss your fleets and empty your resources, the attacker wont get anything. In fact, with a proper defence setup, you’re very likely to cost the attacked a good bit of helium, in addition to the time they spent attacking. The only situations in which PvP is an issue are when you have a conflicting territory space, or when helping your corp capture a Resource Bonus Planet.
3. Wallet Warriors will always be ahead of you. This is something you can’t really help; though there are a few ways you can counter this. The simplest, of course, is to ignore them. There’s little to nothing they can do the hurt you, and they often drive prices down making it easier for everyone below them to get the blueprints they’re farming.
4. The worst issue with these sorts of games is ego. People randomly cursing eachother out; spamming, posting barely-legible insults, flaming other corps, and the like. While this can’t be completely annihilated, it can be avoided well enough simply by remaining civil and using proper spelling and grammar. This isn’t to say, though, that all verbal sparring can be bad: Pointing out something incorrect that someone else says; reporting the results of an amusing battle; or flat-out comparing numbers is reasonable.
5. What’s the best corps? Well, there are three ways of measuring that: Corps Level, Resource Bonus Planets, and Members. While the first two are important, it’s worth remembering that eventually, every corps can have its levels maxed out, and most top corps will hold their own RBPs… Though, by the time a corps is maxed, many of its members likely will be as well, making the RBPs futile. So, this leaves the members: The most important thing about choosing a corps is finding one that’s well organized, friendly, helpful, and the like. Keep in mind that the number 1 corps may be on the top of the leader board, but this isn’t directly tied to how good the corps will be for you. [Note: As of the time of this writing, The_Federation is the top ranked corps. I’m not at all suggesting they’re a bad corps; simply that you should look for the corps that is right for both your in-game level and your personality.]
tl;dr: PvP makes the game worse for everyone. So does random flaming in chat and the forums.