DK Jungle can be a very tricky track to perform perfectly, with many different opportunities to make the slightest of errors that could cost you a few seconds, or worse, fall off the track entirely.
Your first opportunity to shed some seconds comes in the form of a shortcut following the wooden bridge. Drift right then immediately left to line yourself up to the ledge. Use a mushroom to negate the speed loss of the grass. It's important to be more to the left side of the ledge here, as you risk falling off the right side and missing the blue boost to get the glider. Though it is possible to keep your glider while moving across the three boosters, in our time with the game, we noted it didn't offer an advantage to do so, so land before the first jump and try to collect a coin across each.
It's tough to get 10 coins in a single lap, with only 12 or 13 available across the quickest route around the track. Ideally you'll want 10 within one and a half laps. Collect all four across the first bridge, and try and get at least two across the three boosters on the first lap.
When gliding over the water, keep low to avoid the totem's breath, as it can knock you off your path. Land at the earliest possible opportunity to drift onto the shortcut into the final turn. As long as you hold down drift, you will keep your boost over the small jump, allowing you to speed through the start/finish line.
Mario Kart 8 gameplay video walkthrough: DK Jungle fastest time guide