The neutral is hard to learn. You do need to throw booms when you are in range of limbs, but you also need to make dhalsim afraid to throw out limbs in order to get there. Focus dashes, jumps, walk-forward-blocking, c.mp can stuff some stuff, and even the occasional random flashkick can get you there. Once you get some booms on screen, you can dash up for some pressure and screen positioning. Just make sure you have a plan for when you do get in… Guile has some pretty good pressure options against sim with UDK, s.hp frame traps, throws, and you can even OS backdashes with c.lk > c.lk ~ df.hk or c.lk > c.lk ~ c.hk if you want to keep charge.
Another way to create a good pressure opportunity is to back off, wait for him to whiff something big like a s.hp, and then toss a light boom and dash a couple times. You can also FADC it, but I’m not too big on spending the meter… but it’s there if you need to make something happen. Like I mentioned before, you can also whiff punish his s.hp with c.mp and cancel that into boom. It feels real good.
Now, getting in is pretty important in the neutral, but I would argue not to overdue it. If you get pushed back out then you have to earn your way back in again. Take your time and don’t get impatient. Also, if you have a decent life lead, even 100ish damage, you can sit on it a bit. This forces sim to spend meter on EX fires (keep booms on screen to neutralize them) and coming to you to go for sniper mixups (trickier to deal with… you can try to guess when he will do it and block high, or, if you have the stones, focus dash through and tag him with a backfist on his way down).
For jumping, the right range to jump is the one where his b.hk will whiff if you empty jump. Granted he still has options to AA you there, but it does shut down a few things. It forces him to have to think through his options for a few frames, which means that if you push a button in the air, you might catch him thinking and he won’t AA properly or guess wrong. He can still EX up flame, but that takes meter and an input. He can still jump-back mp, but that puts him closer to the corner. His slide won’t cross you under from that jump range, so you keep your real estate… and real estate is SUPER important in this match. He can wait for you to land and do b.mk xx fire… but you can technically flashkick or U2 through that if you’re crispy and if you did a j.hk or something, you might get him hit or put in blockstun. He can still risk the b.hk AA, but if you empty jumped, you can whiff punish it on landing. Finally, he can U2… but not only is that hard to do, but at that range, Guile has a lot of options which can force sim to look for different stuff and be slow on execution as a result.
NOTE: The most important thing about this, is that you don’t do it all the time. The less you jump, the less chance he will have to figure out what you like to do.
Also note that this is basic “Anti-anti-air” stuff that translates well to just about every matchup, but it works extremely well on characters that have to rely on normal AAs. Sakura? Jump out of range of her c.hp. Guile mirror? Jump just outside of c.hp range. Even with a character like Ryu, if you jump juuust right you can get a lot of players to throw out a bad DP when you empty jump at them from the right range.
Guile is really at home zoning people out and using real estate and really just staying on the ground. Don’t think that this is an end-all trick to jumping in on people and keep its use sparse. Hell, in that sakura example, I can’t think on a single good reason to jump at her at all. Just keep in mind that if you do jump, then jump smart.
Geez… I just wrote a novel on jumping.