Lichess says I am rated 800, can anyone kindly help me improve?

I played chess when I was a little boy. Had to stop for family reasons...came back playing after never touching a chess piece for over fifty years. Now I am retired and in my sunset years. I got back playing. I wonder if I still can improve my game.

Tactics and good books

Play slower games

Analyse ur games

Best would be to play 1 game and get it analyzed. Learn from what other say , and then don't make that mistake in your next game. I would be happy to analyze your game.

As a sidenote, playing slower is important. Playing moves off-the-cuff can be fun, but you're not all that likely to improve doing it. So start by trying your best to make good moves in the first place, taking your time to think things through and, if possible, writing down your thoughts as you play (I often find that I can't understand what I was thinking when I make moves that proved the undoing of my entire game). That way, you can also understand how to correct those apparently-flawed thoughts.

Play correspondence games (use a board), take time to make the moves, search for similar games, try to understang the plan... make the move... repeat.
You can play as many as you like simultaneosly.

Also, find a chess club, play and comment the game with your rival to understang why both made those moves... chess is a social experience. Playing online isn´'t if you don't know why you lose the games.

Find a online chess partner, do a match on slower time control. Use the study tool on lichess to save / analyse the games. Share your thought with your partner and compare both visions. Play again.

Play long time controls, analyse each game & do plenty of tactics training (puzzles). You'll definetly see improvement in your game over time. Keep at it! @Bayabas423

Yes of course you can. At our level, tactical awareness is the most important aspect of the game. Lichess has a puzzle section for improving this.

Also play slower games with an increment,10 + 5 minimum, preferably 15 + 15 or even more so that you have sufficient time to think through each move

I too picked up chess recently and have been solely focusing on tactics and I believe it has improved my game

Bayabas,you are rated 1000 and you tell if you can improve?Of course.
From your elo you can get improve a lot(also double it or more).
Welcome back to chess!