Want to become a better philosophical thinker? A more philosophical person?

If someone wants to be a skilled philosophical thinker, here are some skills and virtues that are needed for that. 

Restraint and self-control: we are familiar with behavioral impulse control, but we also need to control our reactions in speaking and even thinking and not react without adequate understanding. Not patiently seeking that understanding makes thinking about complex issues more difficult. Being able to consider an idea, and ensuring that you understand it accurately, before reacting, is important. 

Defining terms is essential: if someone uses a word that could be used in different ways, the conversation needs to stop and that term defined and then that meaning "stuck with" for that portion of the conversation. Not doing that leads to people talking past each other. Switching back and forth between meanings leads to people being confused and talking past each other, each using the same word(s) but thinking about different ideas.

Think slowly and patiently: attempting to think quickly and aggressively tends to lead to people not being careful in their use of terms and so winding up on different issues, again talking past each other.

Related to defining terms in defining issues, and the ability to distinguish potentially related, but distinct issues is essential. E.g., (a) being justified in holding a belief and (b) explaining to others why that belief is justified and (c) explaining to others why that belief is justified in a way that they will be convinced (in some context) are all different activities. Not understanding that these are distinct activities leads to confusion. Furthermore, each issue and argument is distinct: e.g., that one argument for a conclusion is a bad argument doesn't entail that all arguments for that conclusion are bad; that one definition of a term isn't ideal doesn't preclude there being a better definition. Keeping distinct issues distinct is important.

Not knowing important philosophical results impedes thinking about issues where those ideas are applied. E.g., not being familiar with arguments for global skepticism has consequences for understanding epistemic justification; not being familiar with theories of epistemic justification precludes understanding fallibilism; not being familiar with the potential sources of justification, and possible structure of justification will preclude thinking about how different types of particular beliefs (e.g., mathematical beliefs, religious beliefs, etc.) are or might be justified (or not!). Not understand more fundamental issues prevents applying those basics to more complex, higher-order issues.

All and all, a lot progress in philosophical skill-building is developed by calmly and coolly seeking to understand what's meant when people say things ("What do you mean?") and then trying to assess the reasons that are given, and might be given, for and against various views ("Why think that?"). 

In many important ways, becoming a better philosophical thinker is like learning a musical instrument or learning how to play a sport well: there are real things to be learned, and those things need to be learned and intentionally put into practice, and any bad habits and unproductive ways of engaging that seem "natural" need to be identified and work needs to be put in to overcome them. None of this is easy but the results are often worth it.