@ArtistHan Honestly? I watch the anime more than I read the manga. Not because the manga is in any way of worse quality - it's just that since One Piece is so action-focused, it works great as an animation. Lots of kinetic energy in the punches!
I personally advocate reading/watching all of it, from beginning to end, because it really does kick off with a big old bang, and keeps going in the same manner, mixing dorky, look-I-stuck-chopsticks-in-my-nose hilarity with real dropkicks to the heart, and deadly serious themes like slavery and man's inhumanity to man, etc. - and because Oda is a freaking master of hinting at future events AND bringing back old characters in new and amazing ways - but if if you were to jump on at any point, I'd recommend any of the following as good points to do so:
The Arlong Park-arc (in the anime, it starts with episode 31). With the East Blue-crew mostly gathered, this arc not only starts digging a bit into the backstory of some of the characters, but also introduces one of the top-ranking villains on my Gosh I Want To Punch Them In The Face-list - Arlong the Merman. Seriously intense and emotional, and has made me cry every time I re-watch it.
The Baroque Works-arc (epsiode 62-forward in the anime) Kicks off a long-running plotline with Baroque Works as the antagonists, gets the crew closer to their goal of sailing the Grand Line, AND is a nice lead-in to my next recommended jumping-on point.
The Arabasta-arc - or Alabasta, depending on translation. (episode 92- c.a 130) The long-running Baroque Works-plotline kicks into high gear, AND it features yet another villain on my Gosh I Want To Punch Them In The Face-list - whose name is Crocodile.
So yes, those are my recommended jumping-on points.
And seriously. Wherever you choose to start. Do your best to get over the visual style - which will probably come across as really weird and dorky-looking at first - and try to engage with the characters, because despite the extremely cartoony character design, Oda really does have a deft hand with that most shounen of traits; the incredibly intense, passionate, fierce humanity in all of his characters. Luffy is a big old goof and a half, but the first time he grinds his bleeding knuckles into the face of some wickedly cruel villain, I promise you'll be right there with him, cheering him on.
Eichiiro Oda will break your heart if you let him, and you'll be thanking him for it.
.... /nerdery