Join a club or at the very least find a friend who’ll ride with you. This works on 4 levels.
1) Safety, cars seem to give me a lot more space when there’s 2 of you and you’re easier to spot.
2) Speed, if I look at my Garmins results after a solo ride it’s all over the place, random sprins up hills, miles where I was clearly daydreaming, gettign up a hill quickly ony to take it easy over the top, etc. I get twice as much from a ride in a group as I do on my own.
3) Company, occasionaly a solo century can be a nice bit of me time, other days it can be skull crushingly boring. Even if the other guy/girl has nothing to talk about appart from how he saved 2g by filing down the ends of his QR’s or insists that his ceramic bearings are worth another 5watts in a sprint as they can be lubed with kangaroo jism rather than grease, it’s still company.
4) Cafe stops, groups only brake for cake, it’s a fact and however much you think you look like something straight out the Rapha catalogue sitting there on your own in cycling gear drinking cappuchino at the garden center, people are in fact avoiding you, freak. At least doing this in a group means you’re not alone.
Other tips:
In all but the hottest weather, put a good baselayer on under your jersey, it’ll keep you warm on decents and prevent us seeing your moobs on climbs.
Baggies are not cool, ditto peaked helmets, you’re on a road bike, be comfortable with and embrce a new world of chaffe free comfort.
You can fit all you need in your jersey pockets, if you can’t then a small saddle bag is acceptable. Tri-bags are not, and camelpacks make you look like a mountainbiker trying desperately not to identify with other roadies.
Wave to other cyclists, one day you might need to borrow a tube/pump/gell off them, if they dont wave back don’t take it personaly and go on forums to rant about it, they probably just didn’t see you or were too tired, either that or you were wearing a peak/camelpack/baggies.