Alright… first off, stop jumping in so much, Guy has a floaty jump, its easy to anti air, aside from using elbow to basically bait DPs you shouldn’t jump in on most characters cause certain normals and of course the DPs just beat his air normals. You should stick to mostly jumping when they are knocked down for the majority of the match. Guy isn’t meant to jump in since his air normals aren’t the best. You should focus on poking and feeling around your opponent. Similar to what Bisons and Chun will do. Use st mk/mp/hp/hk, cr.mp/mk, don’t use cr hk often its an easy read when it comes to good opponents and its easily beaten by reaction whatever or Focus. Trust me.
You should focus on getting hard knockdowns, so you should OS Run/Slide when you are poking around with st mp or cr.mp, (St mp buffer the qcf K) if the normal hits the run will initiate and all you need to do is react with mk, if it whiffs nothing will come out, if Run does come out either you buffered too late or you hit mk after the buffer. You can also buffer other moves but at certain ranges LP hozanto will whiff even if you get a counter hit and you would have to spend meter for EX hozanto ( St.MP ~ qcb lp or two punches)
After Target Combo (MP-HP) Runslide. Guy has a safe jump on most of the cast. (Doesn’t apply to characters that have slower wake ups, Cammy, Sagat, Blanka believes there is another but anyways, this will beat 4 frame reversals, (the reversal will come out but you have enough time to block, This won’t beat 3 frame reversals or faster. So Characters such as Ryu,Ken can DP you so you’ll have to empty jump. There are also character with Counters mainly Gouken that can beat your safe jump for free as well. Characters with EX SPD or Armoured grabs or Ultras that can catch safe jump are also a threat so you shouldn’t safe jump them when they have meter as they will more than likely catch you
Outside of Safejumping you should always come down with an OS, Beehol made a video for OS on every character and shows what are useful etc. However his Bison one I typically use MK tatsu just because it will actually beat EX Psycho Crusher rather than avoid it since he used MP hozanto but its up to you on that mark.
You should also use OS when in standard wake up pressure it has its uses every now and then.
You should learn the basis of Guy’s Pressure and mix up game, which consists of LP/MP Hozanto, Run/Stop, Run/Overhead, Bushin flip. you shouldn’t become autopilot though and mix it up with doing nothing or playing it safe with LP hozanto. (I would also suggest using TC rather than st mp alone in the beginning to condition your opponent)
You should know when to conserve meter and when to use it, some jump ins can easily be beaten by cr.mp or cr.mk or even grabbed by TK izuna. (Instant Kaiten Izuna.) This is essential to know because using EX tatsu all the time can result in getting baited for it, and you may even get gipped and only score one/two hits, one hit would do nothing two hits is fine but mostly want to aim for 3-4
Make use of frame traps and tick/kara throw. It’s essential in Guy’s game because throws lead to dirty/fake crossups and Frame traps just lead to big damage.
Learn to use both Ultras and what Ultra is better for the match up. Generally U1 can be used in all matchups due to its combo ability, But U2 has uses in others where the opponent may abuse a move that is “safe” but can be punished by U2, (U2 has a 1 frame start up so any move that is -1 and below can be grabbed if the character is in range and you get the reversal mark. Always aim for reversal. Aside from that U2 actually beats Safe jumps and empty safe jumps.
Guy takes some work, A lot of people say he’s easy but honestly in high level play, most of his gimmicks/traps won’t work, its basically down to solid play and knowing your matchups and making sure to make EVERY little thing you do count, just because is a momentum based character and he can lose that momentum very quickly and its hard for him to get it back especially when you don’t have meter.