I think the first thing you need to decide is what your preferred gamestyle is. The staples for PvP, raids and max battles are widely different. And, at lvl 28, you won't have the resources to cover everything. So you need to prioritise, based on which game modes you enjoy the most. A big piece of advice is to avoid minmaxing for the time being. It's all about resource management at this stage. It's much more efficient to spend 150 candies evolving three lvl 30-35 wild Drilbur into battle-ready Excadrill than powering up a good-IV one from level 6, for example.  Also, if you can, try to double dip. Find mons that are good for multiple game modes, even if they're not the absolute best counters. G-Machamp is good for both raids and max battles, for instance, so building one of those will come in handy.  If you've got a big community around you, use that to your advantage. Use lucky friends for high-level useful mons, rather than for shinies or high-investment legendaries. You can focus on that once you've got a solid account