Congratulations on your mid life (crisis!) career change.
Have you observed how 'low' the every day man dresses? So painful.
Drab colored, ill-fitting, low-budget, hangdog, t-shirt slouching, beer bellied, muffin topped,
dumb, expressionless, rubber shoed, ugly denimed, Old Navy-ed, latest-fashioned, directionless, broken ruddered, nose ringed, basketball jersey, baseball capped....... And that is just the gals they are trying to score on! The fellows are even WORSE! Well, that is the way I see it.
I recommend staying in top physical condition whatever your age and keeping a sharp posture. Take care to appear clean and stay clean. Wear clothes that FIT (doesn't matter if you like it tight or loose).
Twice a week make a point to wear casual shirt, necktie and jacket. Just to stay in the game. Whether it is just to go shopping at the market or make a side trip to the post office. If you are an older fellow like me - it is good for your head.
In all occassions wear leather soled shoes (unless you are exercising). NEVER wear a baseball styled cap unless you are in the privacy of your own home (or exercising, or under 19 y.o.). Stay as far above the unwashed masses as possible. Not hard to do. .
For starters visit a crowded area and observe men your age. Spot the fellows that have a positive impression on you. What is it about their clothes and/or shoes you like? Try to note the details. After some time you will develope a certain profile that appeals to your own sense of style. Go from there to visiting stores. Nice clothes need not be especially expensive. Keep an open mind. Remember, you are ready to indulge in your sartorial whimsies! You are going to have fun.