How much Halachic knowledge is a good thing?

Halacha , or Jewish Law, is the lifeblood of the Jewish people. In the 2300 or so years since Moses received the Torah from G-d at Sinai, we have been studying, teaching it, debating it, and writing it down in countless books. We've even written down the debates and now debate them too! Every Jew who attends some form of religious school - be it full time or after their secular schooling, has learned Halacha in one form or another. But unfortunately some have forgotten it, and some have chosen to abandon it. As it says in the Mishnah: He who studies to learn will know it well enough to learn and teach, but he who studies to do (the commandments) will be able to learn and teach, keep and do.

I would like, to some degree to include myself in the latter group. I spent the ages of 4 to 19 in Jewish schools, learning all about our religion and the various aspects of Jewish life as well as the laws that govern them. I feel that I at least have enough Halachic knowledge to live my day-to-day life, with the occasional call to the Rabbi if I need some extra help or advice.

But the downside to this of course, is that friends and acquaintances of mine who are less versed in Halacha sometimes turn to me for questions when they are unable or uncomfortable talking to a Rabbi. While many times their questions have simple answers that I already know, I always worry that my answers to them will be wrong, and cause them to sin.