Guy's most basic link is the link from a cr. :lp: or cr. :lk: into a target combo :mp:>:hp:. It does not matter if you executed one cr.:lp:/cr. :lk:, or two or even three. That link is going to be big part of your game, and it is not exactly an easy one to perform.
On block, this is not a safe link. In other words, when you perform a target combo after a cr.:lp:/cr. :lk: and your opponent is blocking, he can hit you with a reversal move (dragon punch, headbutt, command grab) in the space between the crouching move and the first st.:mp:.
On hit, you cannot be reversaled, of course because it comboes, but it is not hard to miss the timing. So what you have to do here is make your hands never miss the timing for this link. And that's when the plinking part comes into scene. I say you plink the first st. :mp:of the target combo, so you have better chances of not missing the link. We will go back to that later.
For understanding plinks, what they are, how do they work and how to perform them, see VesperArcade tutorial chapter 9. There is nothing I can cover here that they haven't covered yet.
About plinking cr. :lk:
This is actually the main plink you should use (alongside with the st. :mp:plink). Instead of just pressing cr. :lk: always worrying about the timing you are pressing it (especially if you like to do two or three cr. :lk: for hit-confirming) since cr. :lk: is not a chain, but a link, and a pretty awkward one if you ask me, you should always plink this link. It should definitely solve the problem once and for all.
Here, your right hand's position plays a vital role in execution. I have seen many people who throw using the middle finger and the index finger (middle finger :lp: and index finger :lk:). Now that is not what you want. You want to position your hand as natural as possible, so I would advise you to position your hand as follows: thumb :lk:; index finger :lp:; middle finger :mp:, ring finger :hp:, little finger :3p: or :3k: depending on your taste. Without this positioning of your hand it is almost impossible to plink cr. :lk: during a real match, since you will have to be turning your hand a lot.
Having that said, one should always plink cr. :lk:. Why? Two simple reasons, one: it is better for linking cr. :lk:s, two: it is also an option select for teching throws (and a very good one, since you have an extra cr. :lk: input there in case there is a window for hitting the opponent). So let us take a look into how that would look, and some uses of it.
First I try without plink, then with plink:
Going back a little bit, above I said that you can make the standing :mp: link out of one, two or three crouching moves, so let's go at them separately, since the linking timing slightly changes from one another, and things you can do to follow them also change. In all the following videos, first, I try to execute the link without plinking, but I have no success. Then I go for the plink and I get 100% execution (well, at least I would get f I did not suck sometimes but...):
One cr. move > target combo (:mp: >:hp:):
Two cr. moves > target combo (:mp: >:hp:) (target combo whiffs on some characters unless from max close range):
Three cr. moves > st. :mp: (Target combo whiffs on all characters, so here you have to do a st. :mp:only):
Other links that you are going to be using, and can be better perfomed with plinking st. :mp: are cr. :hp:> st. :mp: (on Zangief, Juri, Chun-li, Cammy, Hakan, Dee Jay, Guy, T. Hawk, Sagat, Dudley and Makoto it is possible to perform a target combo:mp: >:hp:), cl. st. :mk:> st. :mp:, and cr. :mp:> st. :mp:. Here is a video on those three examples:
Other plink exemple is to plink st. :hp: after a cl. st.:hk:, and following that with another plinked st. :mp:, on one of the most badasses combos Guy have, but character specific (works on Guy, Sagat, Dee Jay, Adon, Gouken, Zangief, T Hawk, Dhalsim and Blanka). Here it goes:
Remember you cannot plink :lp:, so the bushin chain (:lp:>:mp: >:hp:>:hk:) link after any cr. move will have to be done only with your timing. But then again, this is not a hard link at all, though the timing to do it from cr. :lp: is different from cr.:lk:. Just practice it for a while, you'll get along.