I've been playing for 2-3 days with 9 hours and 30 minutes game time and with just this much time I can tell that I will continue to enjoy playing osu! specially on multi because there are a lot of nice people you can talk and play with even when you just met them.

Please recommend me some maps that can help me improve on standard osu and tips if you have some

3 days and 9 hours of play time, 850 plays.. You quite enjoy the game a lot. Well, that's a pretty good sign. I hope you enjoy the game as much in the coming times. Do play multi, they're fun.

As for the maps, sorry I don't really play standard so I can't help you.

Since you must really enjoy standard, here are some maps that can help you get a good and easy start!
Doki Doki by Thaehan: beatmapsets/519054#osu/1155154 (this song's a great started for all especially that it's in a loved state!)
Walking the streets of a former hell by ZUN: beatmapsets/13469#osu/50482
Shelter (happy30 remix) by Porter Robinson and Madeon: beatmapsets/527621#osu/1119328
Flower Dance by DJ OKAWARI: beatmapsets/476691#osu/1018238
world.execute(me); by MILI: beatmapsets/470977#osu/1067032 (may want to dim background if sensitive to lots of lights at once!)
quaver by dj TAKA: beatmapsets/873811#osu/1846962 (there are lots of difficulties on this one btw!)
Quiet water by Toby Fox: beatmapsets/393995#osu/860486 (for begginers!)
ILY by Panda Eyes: beatmapsets/653534#osu/1385398 (beware of LOTS of lights o-o)
Highscore by Panda Eyes: beatmapsets/332532#osu/736215 (maybe a bit fast!)

Here are some tips on how you can get better

For any of the songs i mentioned, or any of yours, if you can finish a harder difficulty of a song that has an easier difficulty, put the easier difficulty on Hard Rock and/or Double Time, but if that's the easiest difficulty, put it one easy mode and/or half time and keep practicing!

If you don't know how to play the map correctly or can't memorize it, turn on "Auto" and watch auto play the song! Once you think you've got it, try again and see if it works!

(THIS DEPENDS ON WHAT DEVICE YOU USE TO PLAY OSU STANDARD) If you are using a mouse, or anything i don't mention, i highly recommend getting any kind of drawing tablet! I personally like the WACOM tablets because they are bluetooth and you don't have to have a cord messing you up, all you have to do is set that tablet up and charge it, but using another drawing tablet is perfectly fine if you enjoy it and you think it's easier for you!

I don't know if you noticed, but the easiest maps are ones in a loved state! If you'd want to try out a bit of a harder song than what your level is, look at some loved state maps and play them! Only do this if you aren't looking for a PP (performance points) farm map! These are on-timing and good to try out harder songs to!

Whatever you do.. DON'T. STRESS. ABOUT. THIS. GAME. It's meant to be fun and let you enjoy it! If you feel like your getting frustrated, a recommend take a little break and getting some water or something. Have fun and enjoy it as much as you want!

The only tip i can give you is just to play more and never lose hope