The most overlooked aspect of long-term betting is, without a doubt, proper bankroll management. It's not the most exciting topic, but it's the single most important factor that separates successful bettors from those who lose money over time.
Specialization is key, especially when you're just starting out. Focus on one or two leagues you know inside out on a platform like wplay.
Remember, successful betting is a marathon, not a sprint. Patience and continuous learning are your most valuable assets.