If I started again, I would not start where I did! I spent many hours pouring over individual equities, bonds and similar. In the end, I made some howlers - albeit very educational - and not at huge cost.
Looking back now, I also have made the mistake of having too many different investment types, and lo and behold, built myself what looks like a tracker more than a distinct style. I did not adequately set my goals at first, and that led to a frequently illogical allocation. (and I am not 100% sure I am not in that same boat still!)
A 10 yr backward test of my current book looks like this when compared to a global tracker (VWRL):

So, keep costs low, use the time not fretting about individual stock or performance to learn and test. I would tell my younger self to go for a low cost global tracker to form the foundation of the future. Then, as I learnt more, add themes such as sectors or geographies, etc, based on hard-nosed research and self awareness of risk tolerance.
Then again, it is entirely down to your risk views, and degree of time available , etc etc. Never giving advice, just my personal experiences!!
Best of luck!