Though I would prefer to have company while traveling it is not possible to find willing people to accompany you on each and every trip. Solo travel has its perks and its disadvantages.
1. You can twist your plans whichever way you like. If you want to stay another day at a particular place(and this you had not decided before) you can do it without anyone complaining.
2. You have to worry about only your preferences and not manage a group with varied expectations.
3. Since you have no one to share the cost of lodging, transportation etc you will have to manage your budget carefully(that is if you plan to travel frugally)
4. It sometimes gets boring to not have company. You will meet a lot of strangers, fellow tourists on the way but nothing beats times spent with close friends who share the same interest of traveling.
5. Public transport and dharamshalas, hostels etc are the best friends of solo tourists.
6. Always let someone(preferably your family) know your whereabouts. If you are going to a place where network is patchy then inform your family about the same.
7. A lot of places like hotels, wildlife sanctuaries etc make it mandatory for people to provide their details. Do not try to avoid this.
8. Beware of people(this I have seen mostly in North India) who may try to drug you by offering you eatables. Never accept anything to eat from strangers in buses, trains etc.
9. Learn to pack the bare essentials.
10. Most tourists places are safe(the Government gets a lot of flak if some incidents happen in a tourist place so they are more careful) even destinations in UP and Bihar. But try to avoid venturing in unknown areas of a town during the night.
11. Follow local news and newspapers. You do not want to arrive in a town and find yourself in the middle of a strike or bandh.
12. Do not hesitate to take help of the locals. They are helpful 99% of the times. They are your best bet to get to know the public transport system in a town.
13. If you are heading to a place and you don't know the language there learn a few basic words.
14. Read up a little about the places you would be visiting.
Solo travel can be a challenge but at the same time it is very liberating. Personally I have seen that if I don't expect too much out of it(life changing experience, I will get an insight into some hidden ultimate truth etc) I enjoy more, but this is strictly my opinion.