How can I go from the Army Reserve to the Active Duty Army?

Unfortunately the need for 42As is slowly diminishing in the operations overseas. Your best bet is Tour of Duty or talk to your unit to see if they can look around for you to see if there is anything within your state, otherwise, the Army is going back into "peacetime operations" so deployments and budgets are becoming fewer and further between. Another option, probably honestly the best thing to do is, go to your NCOES schools. If you haven't been to WLC yet......GO, if you have, see if you can get a jump on ALC/SLC, or just look into schools that they can send you to, find out what is needed in your unit/battalion/brigade and see if you can goto school to get qualified for that, for instance Master Fitness Trainer (if your pt is high enough) is something that not very many units have, get your combatitives certifications, instructor course, there's literally hundreds of schools you could go to that's not the "sexy" ranger, SF, pathfinder, chest candy schools, but they'll still give you promotion points and some will be helpful in civilian life. So best advice out of all that, use this time to work on your career and give your career meaning that way.

Personnel Force Initiative (PFI) has a website that it advertises positions on as well. I would recommend to go find a local retention NCO, and he should be able to find you a unit. No guarantees that you will deploy, but worth a shot. It took me four years in a row to finally get on AGR. Keep submitting the packet in AKO. Eventually there will be a needd, depending on your MOS. The rank is right.

Another avenue is to look into the AGR program

I would have to agree with a few posts but also disagree.
As a 42A in the AGR program I can tell you that 75% of positions loaded into Tour of Duty already have someone in line for it. Reserve Units now days have to load positions in TOD in order to get ADOS orders for Soldiers. Example: I had a Soldier who used all her AT days for the FY but we wanted to send her to a training for 6 days. We had to load the position in TOD as if it were a vacancy. Once loaded, the Soldier had to go in and "apply" for it. After that we simply closed the position, offered it to her and got her orders. Sounds crazy but it's true. PFI is a good one, i tried it before AGR but got nowhere. It's worth a shot though. As for 42A being over strength in the AGR program, it is however there is always someone getting out, retiring, medical discharge etc. I PCSd to my new duty station in June, saw a SPC 42A with great potential, assisted him in submitting an AGR application on the HRC website and on 8 Jan he PCSd to his first duty station. Looking at the AGRMIS report I can tell you that it's worth a shot. As the MSG said, somethings are career Enders but as long as you have a clearance, never been asked to leave the AGR program and are not flagged you should be good. And if your troubles came from the NG unless it's severe it probably won't follow you on your AGR application. It took me 2 years to get in the AGR program, so don't give up. It was hard for me but I helped two Soldiers get positions 6-9 months after they applied. Just make sure this is what you want to do, being AGR is great but we need great leaders in the program that can help Units and take care of Soldiers.
If you need help feel free to reach out

If you are unable to get a tour and want to go AD you must get a conditional release from your unit to go active.

I am a National Guardsmen on an ADOS tour currently. I went through Tour of Duty and got picked up on my first try. I would say you have to bring your A-game when you are applying to these jobs. A lot of times there are plenty of applicants. So they can be very choosey. It is hard to get a gig there if you don't have some unique job skill or a lot of experience. Also, being in a field that is unique or requires special skills helps you out. But if you are just a regular joe that is just MOSQed then you aren't going to get much attention there.

SPC Riello, as a former 42A, I spent almost my entire career as a duel MOS 42A/31B, in the National Guard. I can tell you, as a 42A you are just about in a dead end MOS, it took me almost 18 years to see that, and my BN CSM told me, "taking care of the Soldiers first is a noble gesture, but you have to take care of yourself first." I ended up reclassing from 42A to 31E and got my E6. You as a young 42A, make sure you check the boxes, (WLC, PT, WPN, civilian education) get those points get promoted. Consider a reclass to a critical MOS. Now for the deploying part, check with state G-1. They have a list of critical MOS that need to be filled, because some units may be understrength and need bodies. Now for reserve to active, like others have said in the posts below, talk to a RA Recruiter, to find out if you can be accepted, and if yes get a conditional release signed by the TAG (CG) and again make sure you have all your ducks in a row, (no adverse action).
Hope this helps.

Talk to your recruiter is the first step, request and early release from your unit, this has to go up to BN and BDE for approval. Ensure the AC recruiter has a position for you prior to requesting a release!

Use your chain of command and beyond that contact higher headquarters and speak to mobilization officer/NCO

Go go the recruiting command and work hard and then move on with your career. Talk to your leadership to get promoted to SGT first.