Supersam most of what has already been said is the best advice you will get, but the things to focus on are:
You will know your capaability of your bladder, don't waste time in or queuing for the toilet have your last drink on course 30 mins before the first race.Remember after so many its a p iss per pint.
Know your bets before getting to the course, they are all trying there are no horses trying to get a good handicap mark for later on.Don't listen to idle gossip they most likely know as much as you.
Try to see as much as possible, the gold cup winner going into the winners enclosure on the Friday for example ( i will never the forget Best Mate going in after his 3rd win_)these are memories that can not be taken away from you.
Most of all enjoy yourself as you said you are in your early 20's, most of us on here have seen many Cheltenham
festivals you are just starting out. We were all in your shoes once, after this year you will join us in carrying o on the tradition to others, they say that horse racing doesn't appeal to the younger generation but obviously it does.
Watch out for pickpockets, you are not the only one to try to make some easy money. I say easy i don't mean it.
Enjoy the craic in the pubs after racing.
Also be pleased in backing a winner, but don't go overboard as tomorrow may be a different day.
As i said earlier enjoy, these are memories you will take to your grave and for Gods sake back a winner or three.

Been to every festival since 2000 .
My greatest memories include
- Istabraq's 3rd champion (2000).
- Brave inca winning the champion hudle ( 2005) -  still the loudest cheer i have ever witnessed there .
- Rooster booster running all over intersky ( 2003 ) 
- Barracouda being cajoled to victory by thierry doumen  from iris,s gift and  limestone lad  ( 2002 )
- waiting for the result of the bumper ( 2002 )  pizarro and rhinestone . Remember looking at the boards when betting opened for the stewards  - 4/7 rhinestone 5/4 pizarro --- it was nearly dark when the result came thru  ( went off at 5.40 then ).
- The sight of stormin norman HARD ON THE STEEL two out on BACK IN FRONT in the supreme  ( 2003 )
- the fastest horse i've ever seen come up the hill - WHATS UP BOYS ( 2000 CORAL CUP )
- Inglis drever ( number 8 ) nearly getting to fundamentalist in the sun alliance novice hurdle  --- just failed to get up .

sorry about the rant but i could go on forever .
THE GREATEST SHOW ON EARTH is the festival --

I forgot, the best thing about the Cheltenham Festival.


There's another one next year.

Bring a hip flask with some nice single malt in it. you will feel even more vindicated sipping away after your horse is led into the winners enclosure.

Gambling

Traffic around town is murder from around 10.30-11.00am.
We drive in from the East (Winchcombe), if you drive down through Prestbury and along New Barn Lane (towards the course) there are farm fields that charge a fiver, you're 5 mins from the course, there are houses nearer who let out their driveway usually for a tenner, but coming from that direction is much better and it's a damn site easier getting away from the course after racing.
You'll be OK coming from this direction until around 11am, it gets a bit bunged up after 11am.
Do not turn right into the course main car park, police will be directing you inthere but go straight on, if you end up in the main car park it'll take you months to get out !
If you get caught up in the town centre you'll be sent on diversions and lose an hour.

Foxhunters is race 5 ?
You'll be fine getting out then
Enjoy !