Solo is always the most thrilling (for me at least) and I've had some of my best raid's when I was alone.
If you're going to rock solo, be prepared that nobody has you 6 but you. You are the only eyes and ears. That can be an advantage, but for a well-prepared team, not so much; you're going to need different tactics.
Tip 1) Grenades: I can't tell you the amount of times these have saved my life. F1 or don't bother, just make sure you give yourself at least 15-20 feet (10ft at minimum), they hit hard. Great against squads, good for escaping, can also be used as a distraction.
Tip 2) Know your map, know your objective: If you're going to be playing solo, you need to know the spots people are hiding, and you need to know where you're going at all times. Every second can count when you finally engage the enemy (scavs or players). Being in the right position at the right moment can make all the difference. I always plan a route to take when going solo/duo (leading) and have a backup plan in case things go south.
Tip 3) Loot quick, stay alert: Looting and gunfire are some of the loudest things in Tarkov, and both give away your position to the enemy. If you're going to loot solo, be quick (know what you want to grab from a body and know what you want to search). Do not sit around in the open, at the very least go prone/crouch or move behind a wall/door. While all this is going on it's very hard to hear, so before you loot make sure the area is clear. Right after a successful kill is the easiest time to be killed yourself, so be alert and listen. After any successful kill I always make a point of checking all potential hiding spots near that body before I loot, otherwise I know I am vulnerable.
Tip 4) When in doubt, move fast: If all else fails and you've found yourself in a bad position, refer to your tips above quickly; can any of these help you? For the sake of argument, however, lets say you're out of grenades, a squad has you surrounded and you've detected them moving in on your location, but you're not sure exactly where. You've got 3 options, engage, camp, or run. Although you might think yourself better than most players on the worst of your days, remember, this is Tarkov and anything can happen. You're probably outnumbered and they have the drop on you. Wait for your moment. If they don't know you're hiding, it's usually easiest to let them come to you for the first kill, unless you can somehow get the drop on multiple enemies. Once you've down the first, be alert for the others and move in quick if they still have not reacted. If they do know where you are, it becomes a bit of cat and mouse (this is where positioning is especially key). Listen for movement if you don't have visiblity and always try to flank your enemy before engaging.
There is a lot more I could go on about, just remember most importantly to try and have fun, otherwise take a break!