We usually like to make an attacking opening lead, to set up tricks in your long suit. Lead the fourth highest (count down from the top), from your longest and strongest suit.
Avoid leading a short suit unless partner has bid the suit.
Avoid leading Aces "from spaces" or "unprotected high cards".
Avoid leading declarer's bid suit.
Remember :
1. Three cards touching or nearly touching each other are sequences against a No-Trump contract. We lead the top.
2. Two cards touching each other in a No-Trump contract, we lead 4th highest.