First thing I would recommend is pace yourself, I find it easy to get overwhelmed when I juggle a full time career, multiple sims, sometimes a family (toddlers can be a burden at time), sometimes a business, while also trying to participate in other events like the dance parties and bar nights from Get Together, festivals from City Living and Island Living, the lounge events from Get Famous, holidays from Seasons, and so on.
Second thing I’d recommend is using the aspirations as starting off points/guides for the various types of game play in the game. Aspirations are a life saver when exploring uncharted territory in the Sims 4.
Third thing, I found University to be an excellent opportunity for sims to build up a whole ton of skills. This ties in with the first thing I suggested, juggling all that game play around along with skill building can be tiresome, so if you want to incorporate skill building into game play in a meaningful way, university is the way to go.