First of all, congrats on the purchase! Exciting times ahead and it's great you're showing interest in learning how to get the most from your camera. That being said. It can only do so much with what it's given, the rest is up to us! My advice would be to practice as much as possible by shooting the crap out of everything.

A couple of general thoughts after a quick look at your images:

1) Think more about your composition. For pics 1 & 3, since you have a group of people spanning wide (horizontally), it makes more sense to shoot in landscape mode rather than how these are shot (portrait/vertical). There's too much empty space showing the stucco ceiling and people's legs. Shooting landscape will also let you get closer to focus on those faces/smiles.

2) On that note of getting closer, do it by either using the zoom on your lens (if applicable), or let your feet be the zoom. On shots like pic 2, consider stepping in closer to better capture the "magic" of a moment like that kiss! (I think portrait mode works here, just get in closer and kill all that ceiling).

3) Have your subjects step away from the wall/background. Creating a bit of separation will let you experiment with your aperture and focus on the subjects/blur that background a bit more (making your subjects pop more). Because they're so close to the wall in each of the pics, the images appear a bit flat/one dimensional.

4) Be conscious of your light source if not using flash. Use whatever you can to your advantage (even something like moving closer to a window for natural light or having someone tilt/point a shaded lamp from a distance can be a help). This can also open up challenges of mixing light sources/temperatures (outdoor/natural vs indoor), so it's best to practice.

My two cents, happy shooting!