I am reading a lot of these posts and I think everyone has made it way too complicated with Daniels charts and Hanson's and Steve Magnus, etc. I am a college coach. Had people come in super slow and end up decent. Had many All-Americans. Do they need to follow Daniels' charts to a "t" and make sure their threshold runs are not too fast and not too slow... not really. It is actually pretty simple and I have a woman I currently train who will be gunning for 1:20 for the Houston Half Marathon this coming weekend. I would give the same advice to someone trying to break 2:30 in the same race...This would be a STARTING point:
Sundays - do a long run of at least 10 miles. Doesn't matter the pace. Just make sure you can at least run the whole thing. Not run/walk it... run it. You can take a quick water break if you need to during the run, but get a good steady run in.
Monday - a "recovery" day from that run. So a 5 miler. Same deal, doesn't matter pace. Whatever pace you feel comfortable doing. At the end of the run, either pick it up the last mile, or do 6x200 on a track with a walk back recovery to do some quick leg turnover.
Tuesday - Always Tempo Tuesday! 1 mile warm up, then 3-8 miles at Tempo pace (and by Tempo, it's easiest to just say a hard sustained effort, where you can say a couple of words if you needed to, but not a whole conversation with someone while you are running). Depending on your fitness level that may only be 3 miles and if you have been training for awhile and are fit, go for up to 8. 1-2 mile cooldown and easy pace.
Wednesday - another "recovery" day from the run. 5-8 miles depending on how you feel from the day prior.
Thursday - Fartlek... 1 mile warm up, then 5 minutes of a hard effort followed by 5 minutes of an easy effort... continuous off and on like that for an hour. As you get fitter, that 5 minutes hard will get you farther!
Friday - another "recovery" day 5-8 miles
Saturday - typically at least 7 miles, but if you feel it will poop you out too much for the next day's long run, then do a little less.
This is kind of the beginner level stuff. If you are feeling good on recovery days, run a little faster. As you get in better shape add in a mile on each day. The woman I am training does a 17 mile long run on Sundays now and anywhere from 70-80 miles a week. Pretty much follows this same sort of pattern every week. Sometimes we do a faster "steady state" run for 8-10 miles instead of a tempo. Sometimes instead of a Fartlek she might do mile repeats on the track, or on a trail. It just depends on the week and what her work schedule looks like, or if the weather is too hot (we are in Texas). So, I think, without overthinking things, this is a good beginner schedule to follow without having to put too much thought into what you are going to do for training, etc. If you want to know more, go ahead and DM me and I can tell you something more specific to what you are trying to accomplish.