Finding your theological balance indeed can be difficult, so here are five tips for those of us still in process.
1. Read your Bible like crazy.
You can't know the Scriptures too well. And by "knowing the Scriptures" I don't just mean the canon-within-a-canon you've chosen for yourself out of three Pauline epistles and a Gospel, or from the books of Matthew and James. Get a few prophets, Old Testament narratives, and even some Torah in there. God gave us 66 books to reveal himself, so ignoring bits will inevitably leave you off-balance. Get this one wrong and the rest won't matter.
2. Read more than one theologian.
Focusing on that one pastor or thinker to the exclusion of others is a recipe for imbalance. As a limited, fallible human, your hero will be myopic somewhere. Expand your horizons. Read outside your tradition a bit. Wander outside your century. Who knows what gems you'll find?
3. Read the key irenic, broadly focused theologians.
Every theologian has hobby-horses and pet issues, but some are well known for their controversies and others for their broad, even-keeled treatments of issues. Look for those theologians who are widely consulted even across traditional boundaries. If there's a Methodist or Catholic being quoted by a Reformed theologian, like Thomas Oden, go ahead and pick him up.
4. Read the key polemical theologians.
I've recently set myself the task of reading some key theologians in the early church controversies: Ireneaus against the Gnostics, Athanasius against the Arians, Cyril against the Nestorians, Augustine against the Pelagians, and so forth. These teachers demonstrated an ability to defend or preserve some necessary tension—some holy imbalance—in the faith. The ability to defend one issue clearly is often a sign of a good grasp on the whole.
5. Read about more than one subject.
This one should be obvious, but if you fixate on one issue, no matter how central it is, you'll have balance issues. It's okay to give sustained attention to interesting or key subjects, but if I've only ever read about the cross and never the resurrection or the ascension, I'll have a skewed view of Christ's person and work. What's more, narrow reading usually obscures a fuller understanding of the couple of subjects I do study since every doctrine is only meaningful within the framework of the whole.
I could easily list more, but the point is, don't be that drunk guy falling off his horse. Study widely, read deeply, and constantly check yourself against the whole of Scripture. Do that, and you may just begin to find your balance.