Good advice from Brian there.
I would add to it that you want the metronome to have an accented sound on beat 1
And also, when you start playing guitar with the metronome, simplify it even further by just strumming on beat 1 for a little while - always know where beat 1 is - and then add in the other beats and…back to Brian’s lesson.
You’ll get it !
check out this thread too
Hi Slobodan,
Welcome and I wish you a lot of fun and Rhythm 
If you have a few pennies to spare and really want to build a good rhythm guitar then buy this
Do you struggle with your rhythm playing and strumming patterns?
Greetings,Rogier
No worries. You’ll get it. It just takes practice and time. Its like rubbing the top of your head with one hand, your stomach with the other, while standing on 1 leg. Once you get that, add in a balance ball (a more complicated strum pattern) 
Hi Slobodan, I highly recommed Justin’s strumming courses. Strumming SOS and Strumming Dynamics. They not only teach you a big variety of strumming patterns, but force you to be accurate by using the metronome and show you how much impact that has on your accuracy and timing.
Hi. I had the same problem on up strokes. It will come eventually but you have to have patience. Muscle memory will get you there.
When I realized I had no idea where my up strum was in the beat, I set the metronome to double time and would strum down on a click then up on a click. That practice got me placing the up strum at the right place. I did the same when I got to 1, e, &, a (16 beat) strumming. I only did it for long enough to get the feel for it. Not a long term strategy.
Sorry Slobodan, we must have posted at the same time.
You’re ok with down strums so no need to simplify that part.
Do you count when you’re strumming? Either out loud or in your head. Out loud is better if you aren’t used to it.
For up strums, say the “ands” as well.
1 and 2 and 3 and 4 and
If you’re not strumming a full pattern, just say “and” where the ups are.
eg. 1 2 and 3 and 4
Yea, we were typing at the same time.
Yes i do count, and it helps a lot, but after some time I fall off again. I will try all the recommendations here, and I hope it will just click at some point like all things so far.
Thanks a lot to you and to everyone else who helped out!
I started using a metronome about a month ago and while I’ve definitely improved I still have a ways to go. Just have patience and practice it. I spend 3-5 mins of each practice session just tapping and counting to the metronome
@brianlarsen had great advice, all of which I’ve been doing. I would emphasize learning to tap your foot with the metronome. You need to internalize the beat. I find it really hard to play if I’m actually listening to the metronome, because I’m listening, focusing on my fretting hand, focusing on my strumming, etc, it’s too much to focus on at one time. The tapping seems to make it easier.
Actually, I was just walking around the city I live in and noticed that my footsteps keep a fairly constant beat, and so I started couting. I’m sure this sounds silly, but i have a feeling this too might help out in the mental part of counting 
And i forgot to mention, this is counting in 8s (one and two and…)
Justin recommends strumming on muted strings to start with. This puts all your focus on the strumming without being distracted by the chords. It helps to make the strumming automatic.
Try a minute or two of muted strumming, then try it with chords.
Welcome to the community!
Here are a couple of lessons from Grade 1 that might help you out.
Strumming On The Beat | JustinGuitar.com
All About Up Strums | JustinGuitar.com
If you’re not already following Justin’s lessons, go back to Grade 1, lesson 1 and start from there.
Strumming in a smooth, comfortable manner and staying in time can take years of practice, so try to be patient with yourself. However, I think strumming is an area where it is very easy to develop bad habits, so the earlier you can start doing it correctly the better.
Great advice here from Brian, really all you need for now.
Know that after enough conscious rhythm practice and playing, you will start to feel the pulse in the music. Timing becomes natural, but not without deliberate practice.
I was having a LOT of trouble with triplets…
What worked for me was very similar to Brian’s @brianlarsen advice above… I tap my foot to the beat on the metronome while clapping hands 3 times in time with the foot taps. This seemed to help me “internalize” the feel or groove of the music. Initially, it was to a slow bpm and gradually increasing to a tempo that was the same as the song I was attempting. Still difficult when strumming but I at least had a good “feel” for when I was off beat & could correct it!
My 2 cents…
Tod
Some very good tips here already, let me add just one that might give you some inspiration on trainign your thythm habits.
I just posted this “Approved Teachers Tip” and I thought it could be valuable to you
Exactly what I thought.
R
Thanks again for help everyone, I’ve tried some of your suggestions and already I’m doing better. I can follow the beat on the down strums, and even the up strums, but when I do fall of i revert to doing 4s. I also found that at some point i stopped thinking about it and just started feeling it. You guys really helped out, and todays practice really gave me the confidence boost i needed. Gonna keep at it till its perfect!
I think practicing with a metronome is the best.