Keep in mind that there are two different kinds of advice that you can get from other domainers:
One that is given for your benefit,
Which is meant to prevent you from making the usual mistakes that are made by many people who might not have enough experience in domaining yet,
And then there is the other kind of advice that is given mainly for the benefit of the person who is giving the advice,
Which is designed to steer you in a certain direction that is meant to protect their own interests and agendas or that of the Registrars, Registries, and other domain related Entities that they are affiliated with.
For those who give you advice for your benefit also keep in mind that what they say might apply to different stages of domaining, so if they say that you should stick to .com or avoid hand registering when you first start domaining it might be so that you can get a little more experience so that you can learn to recognize what a good domain or alternative extension is before you sink all your money into a bunch of useless domains, but as you become more experienced you might then need a whole new set of advice that apply to higher levels of domaining, but that doesn't necessarily mean that the advice that you got at the beginning was wrong, it just means that you might have outgrown those that are for beginners.
In conclusion first try to only listen to those who can be trusted and who want what's good for you and not just for themselves, and secondly remember that even the best advice might only be right for certain stages of domaining and might not necessarily apply to other levels. Also it's important to remember that there are many different routes that can take you to the top of the mountain and so even amongst those who can be trusted there might sometimes be some differences in opinions and then it's pretty much up to you to decide which guru you want to choose to follow.
IMO