Using ones skillset is probably the most advantageous. Good at painting for expample paint houses, pressure washing services seem to be big around here this time of year. Handyman repair sevices work well. A lot of people these days lack the knowledge or desire to do there own small repairs. Maybe a hybrid approach would be best. Earn money doing something and invest the dividends. Along my skill set I have done electrical jobs, welded racks for trucks, built truck beds. Overtime at work also provides money at times. Met a medical professional recently that buys boats in winter and early spring when demand/ prices are low then sells them off in the spring when femand and prices are higher. Probably had 20 rigs sitting there to be sold. The sky is the limit if one has the desire. I like to invest in fishing tackle and hope I can get some memories, smiles, and a good meal in return.
As an afterthought probably one of the best investments that could be made is in education/skill. After all knowledge is power or so School house rock told us
The love for fishing is one of the best gifts you can pass along